Fuel cell system including exhaust heat recovery components

ABSTRACT

A fuel cell system including power modules including fuel cells, and an exhaust flue connected to the power modules. The exhaust flue includes an outer duct configured to receive relatively cool cabinet exhaust from the power modules, and an inner duct disposed inside of the outer duct and configured to receive relatively hot reaction exhaust from the power modules.

TECHNICAL FIELD

The present disclosure generally relates to fuel cell systems and, more particularly, to for fuel cell systems including exhaust heat recovery components.

BACKGROUND

Current fuel cell systems may also be too large to fit into small urban spaces, both outside and inside. Such systems may also be too large to be moved around inside buildings. In addition, the current fuel cell systems do not have a simple way to connect to a ducting system for indoor applications.

SUMMARY

According to various embodiments, a fuel cell system includes power modules including fuel cells, and an exhaust flue connected to the power modules. The exhaust flue includes an outer duct configured to receive relatively cool cabinet exhaust from the power modules, and an inner duct disposed inside of the outer duct and configured to receive relatively hot reaction exhaust from the power modules.

According to various embodiments, a method of operating a fuel cell system comprises operating fuel cells located in hot boxes which are located inside cabinets to generate electricity, providing a relatively cool cabinet exhaust from the cabinets, and providing a relatively hot reaction exhaust from the hot boxes to a flue.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate examples of the disclosed devices and methods, and together with the general description given above and the detailed description given below, serve to explain the features of the invention.

FIG. 1 is a schematic side view of an air-cooled electronics module according to the present disclosure.

FIG. 2 depicts a schematic three dimensional perspective view of an air-cooled electronics module according to the present disclosure.

FIG. 3 depicts a three dimensional view of a fuel cell module cabinet with electronics and other components removed according to the present disclosure.

FIG. 4 depicts a three dimensional view of a fuel cell module cabinet including various electronics and components according to the present disclosure.

FIG. 5 is an isometric view of a fuel cell system according to the present disclosure.

FIG. 6 is an isometric view of a door that may be used in the fuel cell system in an open state according to the present disclosure.

FIG. 7A depicts an exterior view of a door that may be used in the fuel cell system according to the present disclosure.

FIG. 7B depicts an interior view of a door that may be used in the fuel cell system according to the present disclosure.

FIG. 8 is a cross-section view of a door that may be used in the fuel cell system, taken along line A-A in FIG. 7A, showing an airflow through the door according to the present disclosure.

FIG. 9 is a schematic cross-section view of a door that may be used in the fuel cell system, taken along line A-A of FIG. 7A, showing an airflow through the door according to the present disclosure.

FIG. 10 is a side view of a fuel cell system with the side wall removed, showing the door in a closed position according to the present disclosure.

FIG. 11 is a side view of a fuel cell system with the side wall removed, showing the door in an open position according to the present disclosure.

FIG. 12 is an isometric view showing a fuel cell system module including a field replaceable fuel cell module (FCM) with the door removed according to the present disclosure.

FIG. 13 illustrates a perspective view of a fuel cell system including a roof cap assembly, according to various embodiments of the present disclosure.

FIGS. 14 and 15 respectively illustrate cross-sectional views of the roof cap assembly of FIG. 13 in first and second positions, respectively.

FIGS. 16 and 17 illustrate side cross-sectional views of the fuel cell system of FIG. 13, when the door of the fuel cell system is closed and open, respectively.

FIG. 18 illustrates a three dimensional view of a fuel cell system module including a ventilation module, according to various embodiments of the present disclosure.

FIG. 19 illustrates a three dimensional view of the ventilation module of FIG. 18.

FIG. 20 illustrates a perspective view of a fuel cell system configured for indoor operation, according to various embodiments of the present disclosure.

FIG. 21 is a top plan view of the fuel cell system of FIG. 20.

FIG. 22 is a side view of the fuel cell system of FIG. 20.

FIG. 23 is a top cross-sectional view of a ventilation assembly of FIG. 20.

FIG. 24 is a perspective side cross-sectional view of the ventilation assembly of FIG. 23.

FIG. 25 illustrates a partially exploded, three-dimensional view a fuel cell system according to various embodiments of the present disclosure.

FIG. 26 is a schematic illustration of system having stacked fuel cell modules with a shared exhaust plenum according to an embodiment.

FIGS. 27A-27D are plan views of different configurations of fuel cell modules according to various embodiments.

FIGS. 28A-28C are respective top view, side view and front view of a shock damper according to an embodiment.

FIGS. 29A-29C are perspective views of stackable fuel cell modules according to an embodiment.

FIG. 30 is a perspective view of stackable fuel cell modules according to embodiments.

FIG. 31 illustrates a prior art shipping container.

FIG. 32 is a perspective view of a stackable power system according to an embodiment.

FIG. 33 is a perspective view of another stackable power system according to an embodiment.

FIG. 34 is a perspective view of another stackable power system according to an embodiment.

FIG. 35 is a perspective view of another stackable power system according to an embodiment.

FIG. 36 is a side cross sectional view of another stackable power system according to an embodiment.

FIG. 37A is a perspective view of a vertically stacked fuel cell system 3700, according to various embodiments of the present disclosure, FIG. 37B is a schematic view of the system of FIG. 37A, and FIG. 37C is a schematic view showing optional elements that may be included in the system of FIG. 37A.

FIGS. 38A and 38B are schematic views showing the operation of a damper that may be included in the system of FIG. 37A, according to various embodiments of the present disclosure.

FIGS. 39A and 39B are perspective views showing a linear actuator that may be included in the system of FIG. 37A, according to various embodiments of the present disclosure.

FIG. 40A is a schematic illustrating power flow through electrical architecture of a fuel cell system during system startup, and FIG. 40B is a schematic illustrating power flow through the fuel cell system electrical architecture during steady-state operation, according to various embodiments of the present disclosure.

DETAILED DESCRIPTION

The various examples will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. References made to particular examples and implementations are for illustrative purposes, and are not intended to limit the scope of the invention or the claims. It is also understood that the examples shown in the figures are not mutually exclusive. Features shown in one example (e.g., in one figure) may be included in other examples (e.g., in other figures).

Air-cooled Electronics Module

Electronics utilized in fuel cell systems may be cooled, e.g., by air, water, etc. The present inventors realized that when the electronic components are cooled by air, exposing such electronic components to a cooling air flow may cause corrosion and/or short circuits in the electronic components and/or on the electronics boards. This results in reduced lifetime for the power electronics modules. Two or more split (e.g., separate) air zones (e.g., dual air zones) may be provided for electronic components in a housing of a fuel cell system for electronic components. A first air zone may be substantially sealed, and may include pressurized air. The first air zone may include electronic components that are susceptible to corrosion and/or short circuits due to moisture, dust, fuel, or other contaminants in the air. The sensitive electronic components contained within the first air zone may not generate a substantial amount of heat compared to electronic components contained in the second air zone. The pressurized air may substantially prevent the most air and/or fuel and air mixtures from forming inside the first air zone on electronic components. Further, because the pressurized air is also substantially stagnant, moisture and other contaminants cannot enter the sensitive electronic components freely (e.g., there is no or limited air flow within the first air zone). A second air zone may include electronic components that are less susceptible to corrosion and/or short circuits due to moisture, dust, fuel, or other contaminants in the air. The less sensitive electronic components contained in the second air zone may generate a substantial amount of heat as compared to those contained within the first air zone, and therefore, may need cooling by air or other coolant flow. The less sensitive electronic components may be the major heat sources/generators and the electronic components in the second air zone may generate more heat during operation than the electronic components in the first air zone. An airflow with a speed may be provided (e.g., by one or more fans) in the second air zone to provide sufficient cooling for the heat generating electronic components contained therein. With the split air zones configuration, stagnant, substantially moisture free air is provided to the moisture sensitive lower heat generating electronic components contained within the first air zone, and flowing cooling air is provided to the less moisture sensitive, higher heat generating electronic components contained within the second air zone.

FIG. 1 is a schematic side view of an air-cooled electronics module 2 according to the present disclosure. The air-cooled electronics module 2 may be included in a fuel cell system module 100 (shown in, e.g., FIG. 4). The electronics module 2 may include a housing 1. The housing 1 may define a volume or space for containing various electronic components. In one example, the housing 1 may be separated into a first portion 4 (a first air zone 4 or a non-air flow region 4) and a second portion 6 (a second air zone 6 or an air flow region 6). These two separate portions (e.g., air zones) allow for separation of the air contained in the electronics module 2. The first portion 4 may be configured to contain one or more electronic components utilized in the fuel cell system module 100, including, for example, one or more DC/DC converters 3A (FIG. 2) and one or more control circuits 3B (FIG. 2). The one or more electronic components contained within the first portion 4 may not generate a substantial amount of heat, but may be susceptible to corrosion and/or short circuits due to moisture, dust, fuel, or other contaminants in the air. The second portion 6 may be configured to contain other electronic components, which may generate a substantial amount of heat, and may be less susceptible to corrosion and/or short circuits due to moisture, dust, fuel, or other contaminants in the air. The electronic components contained within the second portion 6 may include for example, a transformer 7 and/or an inductor 9. In some examples, the transformer 7 and/or the inductor 9 may be coated or painted with a protective material to prevent or reduce damages caused by the moisture, dust, fuel, or other contaminants within the cooling air.

Referring to FIG. 1, the heat generating electronic components included in the second portion 6 may need cooling. The electronics module 2 may include at least one fan 8 disposed at least one end of the housing 1 (e.g., a front end, a rear end, or a side end). The at least one fan 8 may blow cooling air into the second portion 6 to cool the components contained within the second portion 6. As depicted in FIGS. 2 and 4, the electronics module 2 may include more than one fan 8 disposed at the front end (or rear end, side end) of the electronics module 2. The electronics module 2 may include a heat exchanger 5 disposed within the housing 1, separating the housing 1 into the first portion 4 and second portion 6. The heat exchanger 5, along with other separator(s), may substantially seal the first portion 4 from air included in the second portion 6, serving as a barrier to substantially prevent the cooling air in the second portion 6 from flowing into the first portion 4, thereby protecting the sensitive electronic components contained within the first portion 4 from moisture, fuel, dust, and/or other contaminants in the cooling air and the air in the atmosphere surrounding the housing 1. Air may flow within the second portion 6 at a desired speed to provide cooling to the electronic components disposed within the first portion 4, as discussed below. Air flow within the first portion 4 may be limited (e.g., substantially stagnant). In one example, the first portion 4 may contain pressurized air (e.g., at pressure greater than 1 atm, such as 1.1-2 atm), which further limits the air flow therein. Heat generated by the electronic components in the first portion 4 may be transferred (e.g., removed), through the heat exchanger 5, from the first portion 4 to the second portion 6 (e.g., by heat exchanging between the air contained within the first portion 4 and the heat exchanger 5), where the flowing cooling air contained within the second portion 6 carries away heat from the heat exchanger 5. Thus, the heat within the first portion 4 may be removed by the heat exchanger 5 and the cooling air in the second portion 6.

The heat exchanger 5 may include any suitable heat exchanging components or devices, such as a separator plate which is made of a thermally conductive material. For example, the heat exchanger 5 may include heat sinks, such as fins. The heat exchanger 5 may include any suitable materials, such as, for example, aluminum, an aluminum alloy, or any other metal or metal alloy that are suitable for heat exchange. In some examples, the heat exchanger 5 may include a horizontal or vertical plate hanging from the heat exchanger 5. For example, the heat exchanger 5 may include at least one fin 11 extending vertically from the heat exchanger 5 toward the second portion 6, as shown in FIG. 2. The at least one fin 11 may include aluminum, an aluminum alloy, or any other suitable material for heat exchange. The fin 11 may take any suitable shape or form, such as plate, honey-comb shape, etc. As the cooling air passes through the fin 11, the heat transferred to the fin 11 from air in the first portion 4 may be carried away by the cooling air (e.g., heat is exchanged between the fin 11 and the cooling air).

Referring to FIG. 1, the first portion 4 of the electronics module 2 may include a one-way inlet or valve 19 and a one-way outlet or valve 15. Although shown in FIG. 1 as disposed at the rear end of the electronics module 2, the one-way inlet 19 and/or the one-way outlet 15 may be disposed at any other suitable locations of the housing 1. When a pressure within the first portion 4 is below a first threshold pressure (e.g., 1.013×10⁵ Pascal or 1 atm), the one-way outlet 15 may be sealed (e.g., closed), preventing air from flowing out of the first portion 4. When the pressure within the first portion 4 exceeds the first threshold pressure (e.g., due to an increase in the temperature of air contained in the first portion 4), the one-way outlet 15 may open to allow a portion of the air contained within the first portion 4 to exit the first portion 4 to the atmosphere outside of the housing 1, thereby reducing the pressure within the first portion 4. When the pressure within the first portion 4 is greater than a second threshold pressure (e.g., 1.013×10⁵ Pascal or 1 atm), the one-way inlet 19 may be sealed (e.g., closed), thereby preventing air from flowing into the first portion 4 from the atmosphere. When the pressure within the first portion 4 is below the second threshold pressure (e.g., due to a decrease in the temperature of the air within the first portion 4), the one-way inlet 19 may open to allow air to flow into the first portion 4 from the atmosphere outside of the housing 1, thereby increasing the pressure within the first portion 4. The first threshold pressure may or may not be the same as the second threshold pressure. In some examples, the one-way inlet 19 and/or the one-way outlet 15 may include a permeable membrane, which is configured to permit air flow through it when a pressure on one side exceeds a threshold pressure.

Alternatively or additionally, the first portion 4 may include a one-way valve 21 located at a suitable portion in the heat exchanger 5 that separates the first portion 4 and the second portion 6. When the pressure within the first portion 4 is below a third threshold pressure (e.g., e.g., 2.026×10⁵ Pascal or 2 atm), the one-way valve 21 may be sealed (e.g., closed), preventing the stagnant air within the first portion 4 from exiting into the second portion 6. When the pressure within the first portion 4 exceeds the third threshold pressure (e.g., due to the increase in the temperature of the air contained in the first portion 4), the one-way valve 21 may open to allow a portion of the air to flow from the first portion 4 into the second portion 6, thereby acting as a pressure relief valve. The air from the first portion 4 may flow through the one-way valve 21 to any suitable location of the second portion 6. In one example, the air from the first portion 4 may flow through the one-way valve 21 to the transformer 7. The one-way valve 21 may be any suitable valve. In one example, the one-way valve 21 may include a permeable membrane. The permeable membrane may be configured to allow the air within the first portion 4 to flow into the second portion 6 only when the pressure within the first portion 4 exceeds the third threshold pressure. The third threshold pressure may or may not be the same as the first and/or second threshold pressures. It is noted that the first portion 4 of the electronics module 2 contains substantially stagnant air except when the one-way inlet 19, one-way outlet 15, or one-way valve 21 is opened.

FIG. 2 shows a schematic three dimensional perspective view of the air-cooled electronics module 2 shown in FIG. 1, according to the present disclosure. As shown in FIG. 2, the air-cooled electronics module 2 may include more than one fan 8 (e.g., three fans) at the front end. In one example, the at least one fin 11 may extend toward the second portion 6 from the heat exchanger 5 that separates the first portion 4 and the second portion 6. As cooling air flows through the second portion 6, the cooling air exchanges heat with the at least one fin 11. Although not shown in FIG. 2, it is understood that the heat exchanger 5 may also include at least one fin 11 extending within the first portion 4 to exchange heat with the air contained in the first portion 4.

As shown in FIG. 2, the air-cooled electronics module 2 may further include an electrical input 12. The electrical input 12 may include electrical connections (wired or wireless) from fuel cell stacks contained within a hot box 13 shown in FIG. 4. The air-cooled electronics module 2 may further include an electrical output 17. The electrical output 17 may include electrical connections (wired or wireless) leading to another component of the fuel cell system, such as, for example, an input/output module 14 shown in FIG. 5 or a power conditioning module 18 shown in FIG. 5. The air-cooled electronics module 2 may include one or more electrical connections 37 (wired or wireless) connecting various electronic components, such as, for example, the DC/DC converter 3A, the control circuit 3B, the transformer 7, and/or the inductor 9.

Fuel Cell Module Cabinet

FIGS. 3 and 4 show examples of the fuel cell system module (e.g., power module) 100 including a fuel cell module cabinet 22. For illustrative purposes, FIG. 3 shows a three dimensional view of the fuel cell module cabinet 22 with other components of the fuel cell system module 100 removed. FIG. 4 shows a three dimensional view of the fuel cell module cabinet 22 with electronics and other components installed therein. The fuel cell module cabinet 22 provides separate air spaces for an electrical cabinet 24 (second compartment) and a fuel cell cabinet 26 (first compartment), wherein the electrical cabinet 24 may maintain a positive gauge pressure while the fuel cell cabinet 26 may maintain a negative gauge pressure. The fuel cell cabinet 26 and the electrical cabinet 24 may be provided in a common frame or housing of the fuel cell module cabinet 22. This design reduces the size of the fuel cell system module 100, allowing the fuel cell system module 100 to fit into small spaces for indoor applications, such as freight elevators and freight corridors. The fuel cell module cabinet 22 may include at least one wall or platform 25 separating the fuel cell module cabinet 22 into the fuel cell cabinet 26 and the electrical cabinet 24. FIGS. 3 and 4 show that the electrical cabinet 24 is stacked on top of the fuel cell cabinet 26. It is understood that in some examples, the electrical cabinet 24 may be provided below the fuel cell cabinet 26. In some examples, the fuel cell cabinet 26 and the electrical cabinet 24 may be arranged side by side.

The electrical cabinet 24 may be configured to contain one or more electronics module 2 shown in FIGS. 1-2. As shown in FIGS. 3 and 4, more than one electronics modules 2 may be disposed in more than one slots provided in the electrical cabinet 24. The fuel cell cabinet 26 may be configured to contain one or more other fuel cell system electronics, such as, one or more power generation components. The one or more power generation components may include a hot box 13 containing one or more fuel cell stacks and a balance of plant (BOP) sub-system 27 including blowers, valves, and control boards, etc. FIG. 4 also shows that the each electronics module 2 may include more than one fan 8 (e.g., three fans).

Fuel Cell System

FIG. 5 shows a fuel cell system 10 according to the present disclosure. The fuel cell system 10 may contain fuel cell modules and components described in U.S. patent application Ser. No. 11/656,006, filed on Jan. 22, 2007, and U.S. Pat. No. 8,440,362 B2, issued on Sep. 23, 2011, the contents of which are expressly incorporated herein by reference in their entireties. The fuel cell system 10 may be modular, i.e., it may include one or more fuel cell system modules 100 and other modules. The modular fuel cell system 10 may allow for flexible system installations and operations. The modular fuel cell system 10 allows for flexible scaling of installed power-generating capacity. The modular fuel cell system 10 also increases reliability in power generation, and increases the flexibility of fuel processing and the flexibility of power output voltages and frequencies with a single design set. The modular design results in an “always on” unit with high availability and reliability. For example, when one fuel cell system module 100 is taken off line (e.g., for maintenance, repair, or replacement), other fuel cell system modules 100 may not be affected, and may continue to operate. The modular design also provides an easy means of scaling to meet specific requirements of customers' installations. For example, when power demand increases, the modular design makes it easy to increase the number of fuel cell system modules 100 to generate more power. The modular design also allows the use of available fuels and required voltages and frequencies, which may vary by customer and/or by geographic region.

The fuel cell system 10 may include one or more fuel cell system modules 100 described above with respect to FIGS. 3-5. The fuel cell system 10 may also include one or more fuel processing (or fuel input) modules 16. The fuel cell system 10 may include one or more power conditioning (e.g., electrical output) modules 18. The fuel cell system modules 100 may be electrically and/or fluidly connected with at least one of the fuel processing module 16 or the power conditioning module 18 through wires, cables, and/or conduits provided within the fuel cell system 10, e.g., in the base 20. For example, the fuel cell system module 100 may be electrically connected with the power conditioning module 18 and/or the fuel processing module 16 through wires provided in the base 20. The fuel cell system module 100 may be fluidly connected with the fuel processing module 16 through fluid conduits (e.g., pipes) provided in the base 20, and may receive fuel, such as de-sulfurized fuel, from the fuel processing module 16.

The power conditioning module 18 may be configured to deliver direct current (DC), alternating current (AC), or both. The power conditioning module 18 may include a mechanism to convert DC to AC, such as an inverter. The fuel cell system 10 may include any number of fuel cell system modules, such as 2-30 fuel cell system modules 100. For example, the fuel cell system 10 shown in FIG. 5 includes six fuel cell system modules 100 (arranged side by side in a row), one fuel processing module 16, and one power conditioning module 18. The fuel cell system module 100, fuel processing module 16, and power conditioning module 18 may be disposed on a common base 20. Base 20 may also provide a common space for wiring cables, power lines, conduits that may connect the fuel cell system modules 100 with the fuel processing module 16 and/or the power conditioning module 18. Each of fuel cell system modules 100, fuel processing module 16, and power conditioning module 18 may include its own cabinet. Alternatively or additionally, as will be described in more detail below, the fuel processing module 16 and the power conditioning module 18 may be combined into a single input/output module 14 disposed in one cabinet.

Each of the fuel cell system modules 100 include the fuel cell module cabinet 22, which may be separated into the electrical cabinet 24 and the fuel cell cabinet 26. The fuel cell cabinet 26 may be configured to house at least one hot box 13. Each hot box 13 may contain one or more stacks or columns of fuel cells (not shown for clarity), such as, for example, one or more stacks or columns of solid oxide fuel cells having a ceramic oxide electrolyte separated by conductive interconnect plates. Other fuel cell types, such as Proton Exchange Membrane (PEM), molten carbonate, phosphoric acid, etc., may also be included in the hot box 13. The fuel cell stacks may include externally and/or internally manifolded stacks. For example, the fuel cell stacks may be internally manifolded for fuel and air with fuel and air risers extending through openings in the fuel cell layers and/or in the interconnect plates between the fuel cells.

Alternatively or additionally, the fuel cell stacks may be internally manifolded for fuel and externally manifolded for air, where only the fuel inlet and exhaust risers extend through openings in the fuel cell layers and/or in the interconnect plates between the fuel cells, as described in U.S. Pat. No. 7,713,649, issued on May 11, 2010, the content of which is expressly incorporated herein by reference in its entirety. The fuel cells may have different fuel/air flow configurations. For example, each fuel cell may have a cross flow configuration (where air and fuel flow roughly perpendicularly to each other on opposite sides of the electrolyte in each fuel cell), a counter flow parallel configuration (where air and fuel flow roughly in parallel to each other but in opposite directions on opposite sides of the electrolyte in each fuel cell), and/or a co-flow parallel configuration (where air and fuel flow roughly in parallel to each other in the same direction on opposite sides of the electrolyte in each fuel cell).

The fuel processing module 16 may include a cabinet which contains components used for pre-processing a fuel, such as, for example, adsorption beds (e.g., de-sulfurizer and/or other impurity adsorption beds). The fuel processing module 16 may be configured to process different types of fuels. For example, the fuel processing module 16 may include at least one of a diesel fuel processing module, a natural gas fuel processing module, or an ethanol fuel processing module in the same cabinet or in separate cabinets. A different bed composition tailored for a particular fuel may be provided in each fuel processing module 16. The fuel processing module 16 may process at least one of the following fuels: natural gas provided from a pipeline, compressed natural gas, methane, propane, liquid petroleum gas, gasoline, diesel, home heating oil, kerosene, JP-5, JP-8, aviation fuel, hydrogen, ammonia, ethanol, methanol, syn-gas, bio-gas, bio-diesel and other suitable hydrocarbon or hydrogen containing fuels. In some examples, a reformer 17 may be included in the fuel processing module 16. In some examples, the reformer 17 may be thermally integrated with the fuel cell stack(s). In such examples, a separate reformer 17 may be disposed in each hot box 13 in a respective fuel cell system module 100. In some examples, if internally reforming fuel cells are used, an external reformer 17 may be omitted. The fuel processing module 16 may be fluidly connected with the one or more fuel cell system modules 100, e.g., via conduits provided in the base 20, to provide processed fuel (e.g., de-sulfurized fuel) to the one or more fuel cell system module 100.

The power conditioning module 18 may include a cabinet that contains components for converting DC power generated by a fuel cell stack including in the fuel cell system module 100 to AC power (e.g., DC/DC and DC/AC converters described in U.S. Pat. No. 7,705,490, issued Apr. 27, 2010, the content of which is expressly incorporated herein by reference in its entirety), electrical connectors for AC power output to a power grid, circuits for managing electrical transients, a system controller (e.g., a computer or dedicated control logic device or circuit). The power conditioning module 18 may be configured to convert DC power from the fuel cell modules to different AC voltages and frequencies. Designs for 208V, 60 Hz; 480V, 60 Hz; 415V, 50 Hz and other common voltages and frequencies may be provided. The power conditioning module 18 may be electrically connected with the one or more fuel cell system modules 100, e.g., via wires provided in the base 20, to provide power to the fuel cell system modules 100 and receive power generated by the fuel cell system modules 100.

Referring to FIG. 5, in some examples, the fuel processing module 16 and the power conditioning module 18 may be housed in one single input/output module 14 with a common cabinet. When a single input/output module 14 is provided, the fuel processing module 16 and the power conditioning module 18 may be disposed vertically (e.g., power conditioning module 18 may be stacked above or below the fuel processing module 16 de-sulfurizer canisters/beds) or side by side with one another within the single input/output module 14.

As shown in FIG. 5, one input/output module 14 may be provided for one row of six fuel cell system modules 100, which are arranged linearly side by side on one side of the input/output module 14. The row of fuel cell system modules 100 may be positioned, for example, adjacent to a building for which the fuel cell system 10 provides power. While one row of fuel cell system modules 100 is shown in FIG. 5, the fuel cell system 10 may include more than one row of fuel cell system modules 100. For example, the fuel cell system 10 may include two or more rows of fuel cell system modules 100 stacked back to back, end to end, side by side, or stacked one onto the other.

The fuel cell system 10 is readily scalable. For example, any suitable number of fuel cell system modules 100 may be provided in the fuel cell system 10 based on the power needs of the building or other facility serviced by the fuel cell system 10. The fuel cell system modules 100 and the input/output module 14 may also be provided in other ratios. For example, in some examples, more than six or less than six fuel cell system modules 100 may be provided adjacent to one input/output module 14. Further, the fuel cell system 10 may include more than one input/output module 14 (e.g., two input/output modules 14 each containing a separate fuel processing module 16 and a separate power conditioning module 18). Although in the example shown in FIG. 5, the input/output module 14 is disposed at the end of the row of fuel cell system modules 100, the input/output module 14 may also be disposed at other location of the fuel cell system 10, such as, for example, in the center of the row of fuel cell system modules 100. Depending on the customer's specification (e.g., demand of power), one or more fuel cell system modules 100 may be added to the fuel cell system 10, or one or more fuel cell system modules 100 may be shut down or removed from the fuel cell system 10.

The fuel cell system 10 may be configured in a way to ease servicing of the system. The routinely serviced components (such as the consumable components) may be placed in a single module to reduce the amount of time for service. For example, a purge gas and de-sulfurizer material for a natural gas fueled system may be placed in a single module (e.g., the fuel processing module 16 or the combined input/output module 14). A service person may only need access a single module or cabinet to service the components during routine maintenance. Thus, each of fuel cell system modules 100, input/output module 14, fuel processing module 16, and power conditioning module 18 may be serviced, repaired, or removed from the fuel cell system 10 without opening the other modules or cabinets and without servicing, repairing, or removing the other modules or cabinets.

For example, as described above, the fuel cell system 10 may include multiple fuel cell system modules 100. In some examples, when at least one fuel cell system module 100 is taken off line (e.g., no power is generated by the stacks in the hot box 13 included in the fuel cell system module 100), the remaining fuel cell system modules 100, the fuel processing module 16, and the power conditioning module 18 (or the combined input/output cabinet 14) may not be affected, and may continue to operate to generate power. Furthermore, the fuel cell system 10 may contain more than one of each type of fuel cell system module 100, 14, 16, or 18. In some examples, when at least one module of a particular type is taken off line, the remaining modules of the same type may not be affected, and may continue to operate.

In some examples, in a fuel cell system 10 including a plurality of modules or cabinets, each of the modules 100, 14, 16, or 18 may be electrically disconnected individually, removed individually from the fuel cell system 10, and/or serviced or repaired individually without affecting the operation of the other modules in the fuel cell system 10, allowing the fuel cell system 10 to continue to generate electricity. The entire fuel cell system 10 may not have to be shut down if one stack of fuel cells in one hot box 13 malfunctions or is taken off line for servicing.

Door

Because of the significant size of the fuel cell stack hot boxes, large stationary fuel cell system cabinets have large cabinet doors. The doors may be one to three meters tall by one to three meters wide and made of metal, such as steel or aluminum. The large dimension of the door results in higher mechanical loading requirements on the cabinet, increased door weight, and increased difficulty of handling the doors. Furthermore, the large doors require a large amount of wasted stand-off space between each cabinet and an adjacent structure (e.g., a building, another cabinet, etc.) to allow the side hinged door to swing open/close.

A conventional door opening mechanism (such as a left or right-sided hinged mechanism) would leave the opened door in a position that could hinder access to the inside of the cabinet, especially in a narrow space, such as an alley, or leave the door in a position that could expose it to damage from other doors or equipment. Furthermore, hinging a door from the side could contribute to door-sag from its own weight and dimensions. An additional issue faced when designing a fuel cell cabinet for outdoor operation is the integrity of the weather seal at each door interface. The seal must be positively assured in order to eliminate the reliability impact of water and foreign material entry to the cabinet.

Furthermore, the doors may be constructed from many parts due to the multiple functions that a door performs, such as protecting the fuel cell hot box 13 from the environment, providing a thermal barrier between the outside of the hot box 13 and the ambient, housing the air filters, providing mounting locations for latches, hinges, and seals, etc. The large amount of parts may impact the quality and placement accuracy of the door.

FIG. 6 shows an isometric view of a door 30 that may be used in the fuel cell system 10 in an open state. The door 30 may be included in the fuel cell system module 100, the fuel processing module 16, the power conditioning module 18, and/or input/output module 14. When used in the fuel cell system 100, the door 30 may be attached to the fuel cell module cabinet 22. The door 30 may be a hatch, an access panel, etc., which may allow the internal components of the respective module to be accessed (e.g., for maintenance, repair, replacement, etc.). In one example, the fuel cell system module 100 and the input/output module 14 are arranged in a linear array that has one or more doors 30 only on one face of each module, allowing a continuous row of systems to be installed abutting each other at the ends. Thus, the fuel cell system module 100 and the input/output module 14 may have doors facing a direction perpendicular to an axis of the module row. In this way, the size and capacity of the fuel cell system 10 may be adjusted, e.g., with additional fuel cell system module(s) 100, input/output module(s) 14, and base(s) 20 with minimal rearrangement of the existing fuel cell system module(s) 100, input/output module 14, and base 20. In some examples, the door 30 to the input/output module 14 may be attached to a side end rather than on a front end of the input/output module 14.

In some examples, the door 30 may include at least one inner portion 32 and at least one outer portion 34. The inner portion 32 forms a framework for the door 30 and includes features to allow the door 30 to be coupled to the fuel cell module cabinet 22 or a frame of the input/output module 14. The outer portion 34 may be coupled to the inner portion 32 and may provide a cover for the door 30. In some examples, the outer portion 34 may include a polymeric material and the inner portion 32 may include a metal material. By forming the outer portion 34 of the door 30 at least partially with polymeric components, the building and painting costs, overall weight, and exterior heat loading may be reduced and the dent resistance of the door 30 can be increased. Flame resistance per UL 746C may be included in the material of the outer portion 34 when needed for specific applications.

In some examples, the entire door 30 is injection molded as a single structure. The injection molded door 30 may incorporate as many features as possible to reduce total part count, provide mounting points, and simplify production of high quality parts. A mold for such a molded door may be configured to allow two different plastics to be co-injected into the same mold, such that the inner side of the door (i.e., the side which faces into the cabinet when closed) is made from a heat and flame resistant plastic sheet, while the outer side of the door is made from a plastic sheet that is weather resistant and aesthetically pleasing without possessing the flame and high temperature resistance. In some examples, the door 30 may be formed with a vacuum thermoforming process. A sheet may first be formed with co-extrusion of two or more plastics that meet UL and cosmetic requirements. The co-extruded sheet may then be vacuum thermoformed to form the door 30.

Because high temperature fuel cells (e.g. SOFCs) operate at high temperatures, the door 30 may be formed to have materials or features that increase the flame resistance of the door 30. If there is no risk of flame or extreme heat exposure, then a standard, low cost, color plastic material may be used to form the door 30. If there is a low risk of flame, additives may be mixed with the standard plastics while maintaining exterior quality of the door 30. For example, co-injection may be used to mold the exterior (e.g., the outer portion 34) using the standard plastics and the interior (e.g., the inner portion 32) using the required UL746C flame resistant plastics. A single, co-injection mold with inserts to allow for needed features may be used to form the door 30. In some examples, when flame resistance is needed per UL746C, the door 30 may feature another type of flame retardant feature on its surface. For example, a flame retardant coating may be added to an inner surface (i.e., the surface facing the inner portion 32) of the outer portion 34. As another example, a separate, flexible flame retardant layer such as cloth may be provided over the inner surface of the outer portion 34. As yet another example, a separate, rigid flame retardant layer, such as an extruded flat plastic, may be added to the inner surface of the outer portion 34. In some examples, various flame retardant materials may be used in combination with one another.

The outer portion 34 may be molded or otherwise formed from a polymer in a variety of colors, eliminating the need for painting. In one example, a substantial portion of the outer portion 34 is made of the polymer material. The outer portion 34 including the polymer may be dent resistant and graffiti resistant. The outer portion 34 including the polymer may be scratch resistant and any scratch that occurs may be less visible than a similar scratch on a metal body and may not cause associated corrosion problems. Further, the outer portion 34 may include additional parts and features that are integrally molded, such as filter housings and fasteners to facilitate easier, faster, more accurate assembly of the door 30 and installation of the door 30. The outer portion 34 including the polymer may reduce costs, labor, and material needed for construction of the door 30. Forming the outer portion 34 with a process such as injection molding allows for better fit and easier assembly of the door 30. A polymer material is lighter than a corresponding part formed of a metal material. A door 30 including a polymer material in the outer portion 34 allows for easier handling, lifting, and shipping.

FIG. 7A depicts an exterior view of a door that may be used in the fuel cell system 10 according to the present disclosure. FIG. 7B depicts an interior view of a door that may be used in the fuel cell system 10 according to the present disclosure. To keep separate air spaces for the electrical cabinet 24 and the fuel cell cabinet 26, the door 30 may include a protruding portion 36 extending between the electrical cabinet 24 and the fuel cell cabinet 26. This separation allows the electrical cabinet 24 to maintain a positive gauge pressure while the fuel cell cabinet 26 maintains a negative gauge pressure. The protruding portion 36 may protrude into the space with a suitable portion (full, half, one third, etc.) of the depth of the fuel cell module cabinet 22. The door 30 may be used as a door for the fuel cell module cabinet 22 and/or the fuel processing module 16, power conditioning module 18, or the input/output module 14 that may contain the fuel processing module 16 and the power conditioning module 18.

Filter Assembly

Fuel cell system cabinets generally include filtration systems to filter incoming cooling air that passes through the cabinets. In high-dust environments, multi-layered filters can quickly become clogged and require frequent changes. Pneumatic back flush filters only work when the air intake is shut down and generally do not work well in always-on fuel cell systems. Water curtain filters, in which a curtain of falling water removes particles form air passing through the water, requires power and water flow, which complicates the operation of the system. Such systems require a water filter for a closed system or a constant water supply for open systems.

The door 30 may include one or more air filtration devices as shown in FIG. 6. The air filtration devices may include air filters, screens, membranes, and other air cleaning components. In some examples, the door 30 may include at least one air filtration device in a space between the inner portion 32 and the outer portion 34. For illustrative purposes, in the example shown in FIG. 6, two air filters 40 are disposed over each other in the space between the inner portion 32 and the outer portion 34 of the door 30. FIG. 8 is a cross-section view of the door 30 taken along line A-A in FIG. 7A, showing an airflow through the door 30 according to the present disclosure. As shown in FIG. 8, the left and/or right edge of the door 30 may include an air inlet 42 configured to allow air to flow from the atmosphere to the space between the inner portion 32 and the outer portion 34 where the air filters 40 are disposed. The air passes through the air filters 40, which filter foreign material (e.g., dust, dirt, etc.) from the air. The filtered air is then provided to the interior of the fuel cell module cabinet 22 (e.g., to the fuel cell cabinet 26 and/or the electrical cabinet 24) through an outlet 44 located in the inner portion 32 of the door 30. The air filters 40 may be provided between the inlets(s) 42 and the outlet 44. The filtered air may act as the inlet air stream that is blown into the fuel cell stacks disposed in the hot box 13 by an air blower disposed in the fuel cell module cabinet 22.

The door 30 may further include other air filtration devices, such as a rough or initial filtering mechanism. The initial filtering mechanism may include one or more perforated screens 46, as shown in FIG. 8, which may filter particulate and water/moisture from the air. The perforated screens 46 may be disposed in the air flow path between the air inlet 42 and the air filters 40. Each screen 46 may have an “L” shape when viewed from the top of the door 30. By pre-filtering the incoming air, the door 30 reduces the amount of dust and other particulates fouling the air filters 40.

As shown in FIG. 8, air (shown by arrows) enters from one or more door sides (e.g., left and/or right edge surfaces of the door 30) through the inlets 42 and enters an expansion chamber 41 located between the inlets 42 and the screen 46. The expansion chamber 41 may be part of the inner space between the inner portion 32 and the outer portion 34. In some examples, the width of the expansion chamber 41 may be larger than that of the adjacent inlets 42. This allows the air to expand and slowdown in the expansion chamber 41. As the air slows down, dirt, dust, and other particulate matter suspended in air are allowed to drop down to the bottom of the expansion chamber 41 prior to reaching the perforated screens 46. The air then passes through the perforated screens 46 and enters an inner cavity 45 between the inner portion 32 and the outer portion 34 where the air further flows to the plenum in front of the air filter 40. The inner cavity 45 may be part of the inner space between the inner portion 32 and the outer portion 34. The screens 46 may also create turbulence in the air flow. When the air flow becomes more turbulent and turns abruptly, entrained and suspended particulates that pass through the perforated screens 46 are caused further to drop out of the air. Air with reduced foreign material then passes through air filter 40. The air filter 40 creates an inner vertical baffle. In one example, the air filter 40 provides final filtration. Filtered air enters the cabinet through the outlet 44 in the inner portion 32 of the door 30.

The outer portion 34 of the door 30 may be configured to be hinged outward relative to the inner door 32 (as shown in FIG. 6) to aid in quick and easy servicing of the air filters 40 and/or other filtration devices. The hinge may be disposed at the bottom of the frame of the door 30 such that the outer portion 34 of the door 30 swings downward to expose the air filters 40 and/or other filtration devices for maintenance without opening the inner portion 32 of the door 30 to expose the inside of the fuel cell system module 100 or input/output module 14. Thus, the air filters 40 and/or the screens 46 may be serviced or replaced without opening the entire door 30 to the cabinet of the fuel cell system module 100 or the input/output module 14.

As shown in FIG. 6, the door 30 may include one or more frame members 38 holding the air filters 40. The frame members 38 may be configured to pivot outward or to allow only the air filters 40 to pivot outward as shown in FIG. 6. The frame members 38 and/or the air filters 40 may be configured to pivot outward using a pivot located on the bottom end of the frame members 38. The frame members 38 and/or the air filters 40 may be configured to automatically pivot outward when the outer portion 34 of the door 30 is pivoted outward. Alternatively, the frame member 38 and/or the air filters 40 may be pivoted outward manually by a human operator or a machine after the outer portion 34 of the door 30 is pivoted outward. The servicing of the air filters 40 may be performed without breaking the water-tight seal of the inner portion 32 of the door 30. For example, to service the air filters 40, the outer door portion 34 may be tilted away, and the air filters 40 may be lifted out and replaced. After the air filters 40 are replaced, the outer portion 34 is closed by being swung upwards to be latched to the inner portion 32 of the door 30, as shown in FIG. 6.

The shape of the inlets 42 on the door 32 is configured such that the air inlet area is not directly visible from the front of the door 30 and the front of the fuel cell system module 100 or the input/output module 14, thereby improving the aesthetic of the appearance of the fuel cell system 10. In some examples, the inlets 42 may extend along the full vertical left and right edges of the door 30. Inlet pressure drop may be diminished, reducing the parasitic power draw of the fuel cell system 10. In some examples, the inlets 42 may be located on one of or both of the left and right sides of the door 30. When there is a systematic bias in environmental foreign material (e.g., snow, sand drifts, or other debris being blown to the door 30 from one direction), one of the two sides may effectively be in the “lee” (i.e., downstream) of the oncoming wind without being significantly affected by foreign materials, allowing the unit to operate without obstruction even in severe storm conditions.

The configuration of the door 30 as shown in FIG. 8 has several non-limiting advantages. The air passing through the door 30 is significantly cleaner before it even first enters the air filters 40 than conventional doors. No direct power is consumed to perform the first-stage foreign material removal by using the passive filtering of the air as described above. By reducing the amount of foreign materials that reach the air filters 40, the frequency with which the air filters 40 has to be changed is reduced. By extending the life of the air filters 40, secondary costs due to service personnel visits and filter consumables are considerably reduced for the fuel cell system 10.

Passive Air Intake Louver

FIG. 9 is a schematic cross-section view of the door 30 that may be used in the fuel cell system 10, taken along line A-A of FIG. 7A, showing an airflow through the door 30 according to the present disclosure. FIG. 9 shows that the door 30 may contain a passive air intake louver 59 located within the space between the inner portion 32 and the outer portion 34 of the door 30. The passive air intake louver 59 may include a plurality of internal baffles 47 protruding toward the space between the inner portion 32 and the outer portion 34. The space serves as an air flow path, and the baffles 47 are located within the air flow path. The baffles 47 may cause the air flow from the inlet(s) 42 to change its flow direction, e.g., at least 2 times, inside the inner space before reaching the outlet 44. The internal baffles 47 may be formed, for example, with offset opposing rows of c-channels coupled to the inside of the door 30.

The baffles 47 may take any form or shape, such as, for example, strips, rods, plates, or rails. The baffles 47 may be alternatively attached to the inner portion 32 and/or the outer portion 34 of the door 30, in a roughly interdigitated arrangement (e.g., with baffles attached to opposite portions 32 and 34 of the door 30 overlapping or not overlapping in the door thickness direction). The baffles 47 may extend through the entire or a portion of the vertical height of the door 30. The baffles 47 may be arranged in any suitable configuration which substantially prevents the air stream flowing from the inlet 42 from travelling in a straight line to the outlet 44. Instead, the baffles 47 are configured to direct the air stream to travel a serpentine path from the inlet 42 to the outlet 44.

The foreign material (dust, sand, mist, etc.) in the air stream has momentum which causes it to continue moving forward while the air changes direction around the baffles 47. The dust and sand collect in the corners (e.g., at the upstream baffle surface) formed by the baffles 47 and drain out of the door through one or more openings 48 disposed at the bottom of the door 30. Air with significant reductions of dust and dirt exits the louver assembly through outlet 44.

The air intake louver 59 of FIG. 9 may be used together with the screen 46, the expansion chamber 41, and/or the air filter(s) 40 shown in FIG. 8. In some examples, the air passes from the inlet 42 through the expansion chamber 41 and/or the screen 46 before reaching the baffles 47 of the air intake louver 59. The air then passes from the air filter(s) 40, as shown in FIGS. 6 and 8 and into the fuel cell system module 100 or the input/output module 14 through the outlet 44 in the door 30. Alternatively or additionally, the air intake louver 59 may be present in a door 30 that does not include at least one of the screen 46, the expansion chamber 41, or the air filter(s) 40 shown in FIG. 8.

FIG. 9 depicts two sets of air intake louver 59 structures with air entering from two inlets 42 on left and right sides of the door 30. In some examples, more or less than two sets of air intake louver 59 structures may be provided in the door 30 at periodic or irregular, random intervals. In some examples, more than two inlets 42 may be provided in the door 30. Furthermore, while the inlets 42 are shown in the outer portion 34 of the door 30 in FIG. 9, additionally or alternatively, the inlets 42 may be located in the side (i.e., edge) of the door 30 as shown in FIG. 8.

Door Assembly

FIG. 10 is a side view of the fuel cell system 10 with the side wall removed, showing the door 30 in a closed position according to the present disclosure. FIG. 11 is a side view of the fuel cell system 10 with the side wall removed, showing the door 30 in an open position according to the present disclosure. In some examples, the entire door 30, including both of the inner portion 32 and the outer portion 34, may be opened to access the interior of the fuel cell system 10, which includes the fuel cell system module 100 or the input/output module 14. In order to mitigate the door-sag which might result from the torque upon the door 30 when it is opened, door structures of large stationary generators are generally significantly reinforced with expensive and complex structural members.

Some conventional door panel configurations involve removable cabinet doors. With such designs, when a fuel cell system is being serviced, the door panel is removed and set to the side. In the case of large scale stationary fuel cell generators, removable doors are generally not employed because lifting off a large and heavy door assembly would generally require two field service personnel.

According to some examples of the present disclosure, as shown in FIGS. 10-11, the inner portion 32 and the outer portion 34 of the door 30 may be configured to open in tandem (e.g., together) with a substantially vertical and then substantially horizontal swing (e.g., “gull-wing” style). The door 30 opens by being moved up and then at least partially over the top of the fuel cell system 10 in a substantially horizontal direction. The terms “substantially vertical” and “substantially horizontal” include a deviation of 0 to 30 degrees, such as 0 to 10 degrees from exact vertical and horizontal directions, respectively.

As shown in FIGS. 10-11, the door 30 may be mounted onto at least one wall of the fuel cell system 10 with plural independent mechanical arms, such as two arms 50 and two arms 54. For example, the door 30 may be attached to a wall of the fuel cell module cabinet 22, a wall of the fuel processing module 16, a wall of the power conditioning module 18, and/or a wall of the input/output module 14 (which may contain the fuel processing module 16 and the power conditioning module 18). FIGS. 10-11 show one arm 50 and one arm 54 on the right side of the fuel cell system 10. The corresponding arms 50 and 54 on the left side of the fuel cell system 10 are obscured by the right side arms and thus not visible in the side views of FIGS. 10-11. Thus, in the non-limiting example, two arms 50 and 54 are provided on either side of the door 30 for a total of four arms.

The first arm 50 may include a first, substantially straight end 51 and a second, curved end 52. The second arm 54 may include a first, curved end 55 and a second, substantially straight end 56. It is understood that the first arm 50 and the second arm 54 may take other suitable shapes (straight or curved). The second arm 54 may be longer than the first arm 50 or vice versa. The second arm 54 may include a more pronounced curvature at one end. At least one of the first ends 51 and 55 may be coupled to an interior (or exterior) surface of a wall of the fuel cell system 10 at a fixed or adjustable distance relative to each other. For example, both of the first ends 51 and 55 may be coupled to an interior (or exterior) surface of a wall of the fuel cell module cabinet 22, a wall of the fuel processing module 16, a wall of the power conditioning module 18, and/or a wall of the input/output module 14 (which may contain the fuel processing module 16 and the power conditioning module 18). At least one of the second ends 52 and 56 may be coupled to the door 30 at a fixed or adjustable distance relative to each other. The first end 51 may be located closer to the door 30 than the first end 55. The second end 52 may be located above the second end 56 on the door 30.

The angle of attack for the door 30 as it is opening and closing may be adjusted by changing the location of the pivot points on the door 30 and/or on the fuel cell system 10. In some examples, the angle of attack for the door 30 may be adjusted by adjusting the shape and/or length of the arms 50 and 54. A change in the vertical position when the door 30 is closed and horizontal position when the door 30 is opened may be adjusted by changing the location of the pivot points on the door 30 and/or on the fuel cell system 10. Alternatively or additionally, a change in the vertical position when the door 30 is closed and horizontal position when the door 30 is opened may be adjusted by adjusting the shape and/or length of the arms 50 and 54.

As shown in FIG. 11, in the open position, the arms 50 and 54 and biasing members (not shown) cooperate to hold the door 30 in a substantially horizontal orientation above the fuel cell system 10. The movement of the door 30 between the closed position (FIG. 10) and the open position (FIG. 11) as constrained by the arms 50 and 54 has several advantages over a conventionally side-hinged door. The hinge mechanism includes a relatively low number of parts. Site layout required (e.g., clearance required surrounding the fuel cell system 10) with the gull-wing door 30 is smaller than that required for a conventional side-hinged door of the same dimensions because of the shorter path traced by the door 30 as it opens compared to a longer path traced by a conventional side-hinged door. When closing the door 30, the user is aided by the gravity to overcome the force of the biasing members 58.

Further, in the open position shown in FIG. 11, the upper portion of the door 30 may be located over a top surface of the fuel cell system 10 (e.g., a top surface of the fuel cell module cabinet 22) and the lower portion of the door 30 may overhang the opening to the fuel cell system 10 (e.g., overhang an edge of the top surface). In this configuration, the door 30 has the advantage of providing rain and snow protection for a user/operator since the lower portion of the door 30 overhangs from the top surface of the fuel cell system 10. Alternatively or additionally, the entire door 30 may be located over the top surface of the fuel cell system 10 in the open position.

Positioning Hot Box In Fuel Cell System Module

The internal components of the fuel cell system module 100 may need to be periodically removed, such as to be serviced, repaired or replaced. Conventionally, the components, such as the hot box 13 and/or the balance of plant subsystem 27 are removed from the fuel cell system module 100 with a forklift. Conventional fuel cell assemblies may require substantial space on all sides to position a forklift and remove the components from an enclosure, sometimes as much as four to five times the length of the hot box 13.

FIG. 12 is an isometric view showing a fuel cell system module 100 including a field replaceable fuel cell module (FCM) with the door 30 removed according to the present disclosure. As shown in FIG. 12, the fuel cell system module 100 may include a field replaceable fuel cell module (FCM) 70. The FCM 70 may include a hot box 13, such as a cylindrical hot box that may contain the fuel cell stacks and heat exchanger assembly, as well as a balance of plant (BOP) sub-system including blowers, valves, and control boards, etc. The FCM 70 may be mounted on a removable support 72, which allows the FCM 70 to be removed from the fuel cell system module 100 cabinet as a single unit. FIG. 12 shows a non-limiting example of a FCM 70 configuration where the FCM 70 includes a cylindrical hot box 13 and a frame which supports the BOP components. The hot box 13 and the frame are mounted on a common support, such as the removable support 72, which may be, for example, fork-lift rails. Other configurations may also be used. For example, the hot box 13 may have a shape other than cylindrical, such as spherical, cubic, prismatic, etc. The removable support 72 may include a platform rather than rails. The frame may have a different configuration or it may be omitted entirely with the BOP components mounted onto the hot box 13 and/or the removable support 72 instead. The FCM 70 is dimensionally smaller than the opening in the fuel cell system module 100 (e.g., the opening closed by the door 30). According to one example, the FCM 70 may be installed or removed from the cabinet of the fuel cell system module 100 as a single assembly. The FCM 70 may be coupled to the other components of the fuel cell system 10 using a minimal number of quick connect/disconnect mechanisms. For example, the FCM 70 may be connected to water conduits, fuel conduits, and bus bar conduits housed in the base 20 using quick connect/disconnect mechanisms in order to reduce servicing time.

Module Ventilation

FIG. 13 illustrates a perspective view of a fuel cell system 200 according to various embodiments of the present disclosure. The fuel cell system 200 is similar to the fuel cell system 10 of FIG. 5, so only differences therebetween will be described in detail.

Referring to FIG. 13, the fuel cell system 200 includes a roof cap assembly 210. The roof cap assembly 210 covers exhaust ports of the fuel cell system 200. In particular, the roof cap assembly 210 is configured to prevent water and/or other debris from entering the fuel cell system. The roof cap assembly 210 is also configured to direct system exhaust from fuel cell modules 100 in a lateral direction, across the upper surface of the fuel cell system 200. The system exhaust generated by each fuel cell module 100 may include relatively hot reaction exhaust RE and relatively cool cabinet exhaust CE (see FIGS. 14 and 15). The reaction exhaust RE may refer to reaction products formed when fuel cell stack fuel exhaust is reacted with fuel cell stack air exhaust in the anode tail gas oxidizer, and the cabinet exhaust CE may refer to ventilation air that that is blown through the fuel cell module 100 cabinet by a fan/blower without entering the hot box 13 or stacks (e.g., air blown by fan 8 through electronic module 2 of FIG. 1 and/or the bottom area of the fuel cell cabinet 26 of FIG. 3).

However, because the cabinet exhaust CE and the reaction exhaust RE are directed laterally, a problem may exist when a cabinet door 30 to a fuel cell cabinet 26 is opened for service, as there may be interference between open cabinet door 30 and the roof cap assembly 210. In addition, reaction exhaust RE may be directed at the under surface of the opened cabinet door 30 and at a person (technician) standing under the cabinet door 30. Reaction exhaust RE also has the potential to discolor an inner surface of the cabinet door 30 and/or melt sealing gaskets on the cabinet door 30. Another potential problem is that excessive back pressure may occur in the ventilation system of the fuel cell system 200, which can have adverse or potentially damaging effects on the operation of the fuel cell modules 100.

FIGS. 14 and 15 respectively illustrate cross-sectional views of the roof cap assembly 210, when the cabinet door 30 is closed and open, according to various embodiments. FIGS. 16 and 17 illustrate side cross-sectional views of the fuel cell system 200, when the cabinet door 30 is closed and open, respectively. The cabinet door 30 and associated components are similar to those shown in FIGS. 10 and 11.

Referring to FIGS. 14-17, the roof cap assembly 210 includes a housing 230 and a cover assembly 220 disposed on the housing 230. The housing 230 includes a first chamber 232 configured to receive cabinet exhaust CE, and a second chamber 234 configured to receive a reaction exhaust RE. The housing 230 also includes an internal baffle 236 that separates the first and second chambers 232, 234. The housing 230 may also include a redirect 240 configured to prevent water and/or debris from entering an inlet 231 of the first chamber 232, and a redirect 242 configured to prevent water and/or debris from entering an inlet 233 of the second chamber 234.

The housing 230 may include a screen 243 configured to prevent debris from entering the housing 230. A moveable diverter 238 (e.g., ramp or door) may extend between the cover assembly 220 and the housing 230. The housing may include an inclined upper surface 235.

The cover assembly 220 includes a cover 222 having an opening 223, a door 224 connected to the cover 222, and a moveable arm 226 connecting the door to the housing 230. The door 224 may be connected to the cover 222 by a hinge 225.

According to various embodiments, the cover assembly 220 is configured to move between a first position (cabinet door 30 closed position), as shown in FIGS. 14 and 16, and a second position (cabinet door 30 open position), as shown in FIGS. 15 and 17. In particular, when in the first position, the cover 222 is spaced apart from the inclined upper surface 235, such that the inclined upper surface 235 and an opposing portion of the cover form an acute angle. When in the second position, the opposing portion of cover 222 may extend parallel to the inclined upper surface 235, or may contact the inclined upper surface 235. In other words, when moved from the first position to the second position, the left side of the cover 222 may be moved towards the housing 230, while the door 224 pivots on the hinge 225, to move from a closed position to an open position.

According to some embodiments, the cover assembly 220 may include a stopper 237 disposed on the cover 222. When the cover assembly 220 is disposed in the first position, the stopper 237 may be disposed on the housing 230. When the cover assembly 220 is disposed in the second position, the stopper 237 may be spaced apart (i.e., raised up) from the housing 230.

As shown in FIGS. 14 and 16, when the cover assembly 220 is in the first position, the cabinet door 30 is closed, the diverter 238 is disposed in a raised position with respect to the housing 230, and the cover assembly 220 guides the reaction exhaust HE laterally across the housing 230 towards the opening 223. In addition, the housing 230 guides the cabinet exhaust CE laterally towards the diverter 238. Because the diverter 238 is raised, the diverter 238 directs the cabinet exhaust upwards towards the opening 223. Accordingly, both the cabinet exhaust CE and the reaction exhaust RE are mixed and directed through the opening 223 and out of the side of the roof cap assembly 210, at an angle X of about 30 to about 90 degrees with respect to a line N normal to the closed cabinet door 30.

As shown in FIGS. 15 and 17, when the cabinet door 30 is open, the cover 222 may be moved down towards the housing 230, to allow the cabinet door 30 to be positioned over the cover 222, and the diverter 238 is lowered into a substantially horizontal position. The door 224 pivots on hinge 225, as a first portion 224A of the door 224 is raised by arm 226 to open it. Meanwhile, a second portion 224B of the door (e.g., separator) is lowered towards the baffle 236, to prevent the reaction exhaust RE in the second chamber 234 from entering the opening 223.

Accordingly, the cabinet exhaust CE is directed through the opening 223, while the reaction exhaust RE is directed out of the housing in a different direction, through an opening 227 uncovered by the door 224. In other words, the reaction exhaust RE is directed away from an opening in the cabinet 26 exposed by the open cabinet door 30. As such, the reaction exhaust RE is directed away from the cabinet door 30 and/or a person (e.g., technician) located adjacent to the open cabinet door 30, while cabinet exhaust CE is directed under the open cabinet door 30. In other words, when the cabinet door 30 is closed, the roof cap assembly 210 may be disposed in a first position, as shown in FIG. 14, where the cabinet exhaust CE and the reaction exhaust RE may be mixed and directed toward the cabinet door 30, at an angle X of between about 30 and about 90 degrees with respect to a line normal to the door. When the cabinet door 30 is open, the roof cap assembly 210 may be disposed in a second position, such that the reaction exhaust RE is directed at an angle Y of greater than about 90 degrees with respect to the line N normal to the closed cabinet door 30, and the cabinet exhaust CE is directed at an angle Z of less than about 30 degrees with respect to the line N normal to the closed cabinet door 30.

According to some embodiments, the housing may include an actuator 244 to drive the arm 226, and thereby open/close the door 224 and move the cover 222. The actuator 244 may be an electric motor or a spring assembly. The actuator 224 may be configured to operate automatically when the cabinet door 30 is opened. For example, when the cabinet door 30 is opened, the cover assembly 220 may automatically assume the second position, and when the cabinet door 30 is closed, the cover assembly 220 may automatically assume the first position. In the alternative, the roof cap assembly 210 may be operated manually. In other embodiments, an electrical actuator may be used to release a latch to allow the cover assembly 220 to tilt as the cabinet door 30 is opened. Further, such a configuration could be used with a remote control or encoded signal from a hand carried device, such as an electronic key, to provide additional security.

FIG. 18 illustrates a three dimensional view of a fuel cell system module 100 including a ventilation module 300, according to various embodiments of the present disclosure. FIG. 19 illustrates a three dimensional view of the ventilation module 300. The fuel cell system module 100 is similar to the fuel cell system module 100 shown in FIGS. 3 and 4, so only differences therebetween will be discussed in detail.

Referring to FIGS. 18 and 19, the ventilation module 300 is attached to a fuel cell module cabinet 22 of the fuel cell system module 100. The ventilation module 300 may be configured for outdoor use when the fuel cell system module 100 is located outdoors (i.e., not in an enclosed room). The ventilation module 300 may be attached to the back of the fuel cell module 100, opposite from cabinet door 30. The ventilation module 300 includes a housing 320, upon which a cover vent 310 may be disposed. In particular, the housing 320 may include a first bracket 322 and a second bracket 324 configured to mate with corresponding attachment points (not shown) of the fuel cell module cabinet 22. Herein, the housing 320 may be referred to as a vent housing. The fuel cell module cabinet 22 may include a step in back that provides space to insert the ventilation module 300.

The housing 320 includes inlets 326 configured to receive fuel cell exhaust emitted from corresponding openings in the fuel cell cabinet 26, an inlet 328 configured to receive a cabinet exhaust emitted from a corresponding opening in the fuel cell cabinet 26, and an upper opening 325. The housing 320 also includes a fan assembly guide 332, flow guides 334, and baffles 336, as discussed below.

A fan assembly 340 is disposed in the housing 320. The fan assembly 340 includes a fan housing 342, a fan 344 disposed in the fan housing 342, and a handle 346 attached to the fan housing 344. The fan 344 is configured to operate as a reverse impeller to pull the cabinet exhaust into the housing 320, via inlet 328. The fan assembly 340 is configured to be slideably mounted on the fan assembly guide 332. The fan assembly guide may include guide rails configured to guide the fan assembly 340 into an appropriate position with respect to the housing 320. In particular, the fan housing 342 may slide along the rails until the fan assembly 340 is properly disposed in the housing 320, at which point the distance between the rails may decrease, thereby securing the fan assembly 340.

Accordingly, the fan 344 may be replaced without detaching the housing 320 from the fuel cell system module 100. In particular, a technician may grasp the handle 346 to pull the fan assembly out of the housing 320. This allows for fan 344 to be replaced in the field, as well as allowing for other type of fans to be interested into the fan assembly 340, according to particular air flow requirements.

The cabinet exhaust enters the fan assembly 340 through the inlet 328. The cabinet exhaust then exits the fan assembly 340 through openings 330 in the fan housing 342 disposed under the flow guides 334. The fan housing 342 may include a baffle structure that is aligned with the flow guides 334, such that the fan housing 342 guides the cabinet exhaust towards the flow guides 334. The flow guides 334 may include first baffles 334A that extend from the guide rails 332 to the inlets 326, and second baffles 334B that extend along lower edges of the inlets 326. The flow guides 334 are configured to direct the cabinet exhaust towards the baffles 336. The baffles 336 may deflect the cabinet exhaust towards the top of the housing 320 and/or create turbulence in the flowing cabinet exhaust. The flow guides 334 are also configured to direct the reaction exhaust entering the inlets 326 toward the top of the housing 320. As a result, the cabinet exhaust and the reaction exhaust may be mixed inside the housing 320 before exiting the housing 320 through the upper opening 325.

The housing 320 may also include and side vents 338. The cabinet exhaust flowing past the baffles 336 may mix with ambient air entering the housing 320 through the side vents. The housing may also include lower openings 337 and side openings 338 disposed under the baffles 336. Ambient air may also enter the housing 320 through the lower openings 337 and side openings 336. For example, ambient air may be pulled into an area below the housing 320, and then be pulled through the lower openings 337 or through side openings 338 into an area under the baffles 338, as the cabinet exhaust travels across the baffles 336. Accordingly, ambient air may enter the housing 320 and be mixed with the cabinet exhaust and the reaction exhaust, before the mixture exits the housing 320 through the upper opening 325, since the ventilation module 300 is located outdoors and can vent exhaust upwards.

FIG. 20 illustrates a perspective view of a fuel cell system 400 configured for indoor operation, according to various embodiments of the present disclosure. FIG. 21 is a top plan view of the fuel cell system 400. FIG. 22 is a side view of the fuel cell system 400. The fuel cell system 400 is similar to the fuel cell system 200 of FIG. 13, so only differences therebetween will be described in detail.

Referring to FIGS. 20-22, the fuel cell system 400 is disposed in a room RM, wherein the ceiling is omitted for purposes of illustration. The fuel cell system 400 includes fuel cell system modules 100, a ventilation assembly 410 configured to receive exhaust emitted by the fuel cell system modules 100, and transmit the exhaust to an external vent 402 located in a wall, floor or ceiling of a room. The ventilation assembly 410 may be connected to the fuel cell system modules 100 by connectors 404, or may be directly connected to the fuel cell system modules. According to some embodiments, the ventilation assembly 410 may be connected to the fuel cell system modules 100 as described above, such that the ventilation assembly 410 may receive a mixture of cabinet exhaust and reaction exhaust, as described above. In other words, fuel system modules 100 may be connected to ventilation assemblies 300 or 410, depending upon whether the corresponding system is disposed indoors or outdoors.

An upper surface of the ventilation assembly 410 may be substantially planar with upper surfaces of the fuel cell modules 410, since no exhaust is vented upwards into the room. As such, the vertical space occupied by the fuel cell system 400 may be reduced, such that it may be disposed below a ceiling. As shown in FIG. 22, the ventilation assembly 410 may include one or more fans 406 (e.g., suction fans) configured to draw exhaust through the ventilation assembly 410 and out of the room through the external vent 402. In addition, the fuel cell system 400 may include a support structure 408 to support the ventilation assembly 410.

FIG. 23 is a top cross-sectional view of the ventilation assembly 410. FIG. 24 is a perspective side cross-sectional view of the ventilation assembly 410. Referring to FIGS. 23 and 24, the ventilation assembly 410 includes an upper duct 418, a lower duct 420, and an inner duct 412 disposed between the upper duct 418 and the lower duct 420. The inner duct 412 includes exhaust inlets 416 through which fuel cell module 100 exhaust (e.g., a mixture of fuel cell cabinet and reaction exhaust) enters the inner duct 412. The upper duct 418 and the lower duct 420 include air inlets 422 through which external (e.g., room) air may be pulled into the upper and lower ducts 418, 420. A first end 426 of the ventilation assembly 410 is sealed, while a second end 428 is open. The second end 428 may be connected to the fan 406 and/or the external vent 402.

As shown in FIG. 23, the ventilation assembly 410 may optionally include deflectors 424 disposed in the inner duct 412. For purposes of illustration, the air inlets 422 have been omitted from FIG. 23. The deflectors 424 may be configured to deflect incoming exhaust toward the second end 428 of the ventilation assembly 410. While the deflectors 424 are shown as being trapezoidal in shape, the present disclosure is not limited to any particular shape, so long as the deflectors 424 operate to guide the exhaust towards the second end 428. In particular, the deflectors may be arc-shaped, plate-shaped, or the like.

The fan 406 pulls the exhaust 424 through the inner duct 412 towards the external vent 402. In addition, the fan 402 draws ambient air into the upper and lower ducts 418, 420, through the inlets 422, and towards the vent 402. Accordingly, the upper and lower ducts 418, 420 operate to cool the inner duct 412. In addition, any gases leaked from the inner duct 412 are carried by the external air of the upper and lower ducts 418, 420 towards the vent 402. As such, the fuel cell system 400 can be safely operated indoors.

Although the upper and lower ducts 418, 420 are shown as being separate ducts, the upper and lower ducts 418, 420 may be portions of a single duct that surrounds the inner duct 412. In particular, the upper and lower ducts 418, 420 may extend onto side surfaces of the inner duct 412 and connect with one another.

FIG. 25 illustrates a partially exploded, three-dimensional view a fuel cell system 500 for indoor use, according to various embodiments of the present disclosure. Referring to FIG. 25 the fuel cell system 500 includes fuel cell system modules 100 and a ventilation assembly 510 configured to separately receive reaction exhaust and cabinet exhaust emitted by the fuel cell system modules 100. As in the prior embodiment, fuel system modules 100 may be connected to ventilation assemblies 300 or 510, depending upon whether the corresponding system is disposed indoors or outdoors, without making changes to the modules. The cabinet exhaust may be used to prevent or reduce leakage of the reaction exhaust into the room. Only one row of fuel cell system modules 100 and the corresponding elements of the ventilation assembly 510 are shown in FIG. 25. However, the present disclosure is not limited thereto. In particular, the fuel cell system 500 may include a second row of fuel cell system modules 100 (see FIG. 20, for example) disposed parallel to the shown row of fuel cell system modules 100, and the structure of the ventilation assembly 510 may be duplicated or mirrored, such that the ventilation assembly 510 serves both rows of fuel cell system modules 100.

The ventilation assembly 510 includes an outer housing 520 and an inner housing 530. The outer housing is configured to receive cabinet exhaust from cabinet outlets 504 of the fuel cell system modules 100. The inner housing 530 is configured to receive reaction exhaust from system outlets 502 of the fuel cell system modules 100. In particular, the inner housing 530 includes exhaust manifolds 532 and an exhaust conduit 534. The exhaust manifolds 532 receive reaction exhaust from single or adjacent system outlets 502.

The exhaust conduit 534 includes inlets 536 configured to receive reaction exhaust from the exhaust manifolds 532. The inlets 536 are shown as being ovoid for purposes of illustration. However, the inlets 536 may be any suitable shape.

The ventilation assembly 510 may further include a ventilation module 540. The ventilation module 540 may include a first fan 542 and a second fan 544, disposed in a fan housing 546. The fans 542, 544 may be configured to draw air into the ventilation assembly 510. An additional second fan 544A may be included, if the ventilation assembly 510 is configured to operate with two rows of fuel cell system modules 100. However, the ventilation assembly 510 is not limited to any particular number of fans, as fewer or additional fans may be included. The fan housing 546 may be a hollow body, or may be substantially solid, except for through holes in which fans are disposed.

The first fan 542 is disposed in an opening of the fan housing 546 that communicates with the outer housing 520. The first fan 542 is configured to apply suction to the outer housing 520. Accordingly, the first fan 542 may operate to expel the cabinet exhaust from the outer housing 520. For example, the first fan 542 may expel the cabinet exhaust into the ambient environment of the fuel cell system 500. In some embodiments, a first fan 542 may be disposed at each opening 504.

The second fan 544 is disposed in an opening of the fan housing 546 that communicates with the inner housing 530, and in particular, with an open end of the conduit 534. The second fan 544 is configured to apply suction to the inner housing 530. Accordingly, the second fan 544 may operate to expel the reaction exhaust from the inner housing 530. For example, the first fan 542 may expel the cabinet exhaust into external vent 402, and fan 544 may expel reaction exhaust RE into the external vent 402 or a different external vent. However, according to some embodiments, the reaction exhaust may be additionally processed, as discussed below.

The outer housing 520 and the inner housing 530 can be maintained at different pressures. According to some embodiments, the outer housing 520 may be maintained at a higher pressure than the inner housing 530. In other words, the ventilation assembly 510 can be configured to apply higher suction to the system outlets 502 than to the cabinet outlets 504, by controlling the operations of the first and second fans 542, 544. Thus, lower pressure reaction exhaust is prevented from leaking from the inner housing 530 into the room, by the higher pressure cabinet exhaust in the surrounding outer housing 520.

Further, the configuration of the ventilation assembly 510 allows for the cabinet exhaust and the reaction exhaust to be separately exhausted from the fuel cell system 500. As such, in some embodiments, the expelled reaction exhaust may be directed to a heat exchanger 550, via a diversion conduit 548 attached to the housing 546. Therefore, the heat and/or water of the reaction exhaust may be recovered.

According to other embodiments, the conduit 534 may have a double wall-structure, similar to the structure of the ventilation assembly 410 shown in FIG. 24. In other embodiments, the ventilation module 300 of FIG. 19 may be substituted for the ventilation module 540 or multiple ventilation modules 300 may be substituted for one ventilation module 540. Further, the ventilation assembly 510 may also include a pressure sensor 550 disposed in the exhaust conduit 534 configured to determine the pressure in each of the inner housing 530, and a pressure sensor 552 disposed in the outer housing 520 and configured to determine the pressure thereof. If the pressure in the inner housing 530 approaches the pressure in the outer housing 520, the pressure in the outer housing 520 may be increased, and/or pressure in the inner housing 530 may be decreased, by controlling the speed of one or more of the above fans.

Thus, the indoor ventilation assemblies 410, 510 described above use ambient air or cabinet exhaust, respectively, flowing in an outer conduit to prevent the reaction exhaust flowing in an inner conduit inside the outer conduit from leaking into the room.

In a typical installation, fuel cell modules 100 are arranged in columns and rows on the ground. This generally requires on or in the ground facility runs for natural gas, water, power and data. This creates considerable installation cost and also limits power density to the maximum density of modules which can be fit on a given level. Conventional fuel cell modules 100 are typically provided on a single level, avoiding the need for any stacking, but also losing the benefit of high power density through packing.

In an embodiment, power modules, such as fuel cell modules 100, are placed in a face-to-face and back-to-back orientation to form a common inlet plenum space and a common exhaust plenum space. In an embodiment, inlets are provided from the front face and exhaust outlets are provided from the back face. When fuel cell modules 100 are stacked in this way, common plenums are formed without additional ducting or chimney hardware, thereby significantly lowering the cost and practicality of a stacked installation solution.

FIG. 26 illustrates an embodiment having stacked fuel cell systems 10 comprising fuel cell modules (e.g. power modules) 100 with a shared exhaust plenum 2602. As discussed above in regards to FIGS. 3 and 4, the fuel cell modules 100 may include a fuel cell module cabinet 22 which includes an electrical cabinet 24 with air-cooled electronics modules 2 located inside. Located in the fuel cell module cabinet 22 below the electrical cabinet 24 is a fuel cell cabinet 26 which includes the hot box 13. As illustrated, this embodiment includes two rows 2601 of stacked fuel cell systems 10. In this embodiment, the fuel cell modules 100 are configured such that the cold air inlets, such as but not limited to, air inlets 42 in the door 30, are on the outside and the hot exhaust outlets 2603, such as but not limited to, upper openings 227 in the roof cap assembly 210, openings 325 in ventilation module 300 and/or first and second fans 542, 544 in ventilation module 542 of the ventilation assembly 510, and are configured to empty into a “hot aisle” e.g. a shared exhaust plenum 2602 located between the rows 2601 of fuel cell systems 10. If more than two rows 2601 of fuel cell systems 10 are provided, the rows 2601 can be configured such that alternative hot aisles 2602 and “cold aisles”, e.g. inlet plenums 2604, are formed. In an embodiment, a fuel cell system 10 may comprising one or more fuel cell modules 100, one or more fuel processing modules 16, one or more power conditioning modules 18 and/or one or more input/output modules 14 may be provided in a single container 2606. Any suitable container 2606 may be used, such as a shipping container, a rack, a pallet, etc. Containers 2606, each comprising a fuel cell system 10, may then be stacked vertically on another container 2606. A vertical stack 2607 of two or more containers, 2606, such as 2 to 6 containers 2606 may be provided. In an embodiment, vertical stack 2607 of containers 2606 may be arranged in rows such that a hot aisle 2602 is formed between the rows. If more than two rows of stacks 2607 of containers 2606 are provided, then the stacked rows 2601 can be configured such that alternative hot aisles 2602 and cold aisles 2604 are formed.

General Alternative Embodiments

An alternative embodiment includes the use of Co-Gen units (e.g., engines, turbines, battery cabinets) instead of fuel cell modules 100; or combinations of engines, turbines, battery cabinet and/or fuel cell modules 100. Another alternative embodiment includes the addition of fins (not shown) to either divert flows or block recirculation. FIG. 27A illustrates an embodiment in which cross bracing or support walls 2700 provided at the ends of a base 20 of the container 2606, especially if the container 2606 comprises a pallet or an open rack, for extra support. Alternatively, if the system includes compressed natural gas, an exoskeleton may be provided for extra support. In another embodiment, the containers 2606 may be shipping containers with locking mechanisms provided in the corners of the shipping container and/or along the edges of the shipping container 2606. In still other embodiments illustrated in FIGS. 27B-27D, fuel cell modules 100 or containers 2606 housing the modules may be arranged in rectangular, square, triangular, or grid shapes to increase packing density. FIG. 27B illustrates an embodiment in which non-heat generating (e.g. input/output and/or power conditioning) modules are located in zones which are not otherwise used for anything else, i.e. empty spaces 2702 in the configuration. FIG. 27C illustrates an embodiment in which the containers 2606 are arranged in a triangular configuration. The air inlets may be located on the outside of the containers 2606 and the exhaust located in the internal enclosure 2704 formed by the triangular arrangement. Alternatively, exhaust outlets may be located on the outside of the containers 2606 and the air inlet located in the internal enclosure 2704 formed by the triangular arrangement. FIG. 27D illustrates possible configurations which include more than three fuel cell modules 100 or containers 2606 of fuel cell modules 100. The shape of various stacking configurations allow shared structural rigidity when the fuel cell modules 100 or containers 2606 are affixed to each other.

An embodiment includes shipping shock dampers 2800 which may be located in the base of the container 2606 to absorb vibration and shocks while shipping the fuel cell systems 10. An embodiment of a shipping shock damper 2800 is illustrated in FIGS. 28A-28C. In this embodiment, the shipping shock damper 2800 includes an upper mount plate 2804A, a lower mount or wear plate 2804B and a plurality of coils 2802. The shipping shock damper 2800 can be mounted to the container 2606 via bolts or clamps passed through holes in the upper mount plate 2804A. Modules, such as, fuel cell modules 100 can be mounted to the shipping shock damper 2800 via bolts or clamps passed through holes 2805 in the upper mount plate 2804A. The coils 2802 can flex, absorbing shock and vibration and thereby stabilizing the attached modules. In an embodiment shown in FIG. 28C, lower mount plate 2804B of the shipping shock damper 2800 has a first width w. As illustrated in FIGS. 28A and 28C, the upper mount plate 2804A has a larger second width W. However, the upper mount plate 2804A may have a shorter width. In an embodiment, the shipping shock damper 2800 has a length L, which may be as long as the length of the container 2606 or shorter. The total height H of the shipping shock damper 2800 the sum of the thicknesses of the upper mount plate 2804A, the lower mount or wear plate 2804B and the plurality of coils 2802. The holes 2805 in the upper and lower mounting plates 2804A, 2804B may be spaced apart any suitable distance.

In another embodiment, a locking mechanism configured to lock the shipping shock dampers 2800 is provided so that there will not be any sagging over the life of the system 10 when in place at a site. Optionally, the shipping shock dampers 2800 may be locked during while shipping. In another embodiment, anti-roll (sway bar) control is provided within a vibration isolation system. The sway bar can be free to move during dynamic situations to provide roll control during shipment and then may be lockable for static install. In an embodiment, the anti-roll control is active after installation to aid in mitigating seismic vibrations.

FIGS. 29A-29C illustrate additional embodiments of stackable containers 2606. As illustrated in FIGS. 29A and 29B, stackable containers 2606 can be configured to slide toward or away from each other. For example, the stackable containers 2606 may include wheels or rollers and be slidably mounted on tracks. The containers 2606 may slide toward each other and be locked together during shipping, as shown in FIG. 29A, and then unlocked and slid apart at the power generation site to provide a plenum 2602 and/or 2604 between them, as shown in FIG. 29B. Other suitable mechanisms allowing objects to slide toward and away from each other may be used as well. In an embodiment, locks 2906 are provided for using standard shipping container locking mechanisms at corners and edges to hold the power modules in place as shown in FIG. 29A. In an embodiment, container 2606 may also include locks or fasteners to lock the container 2606 to a ship or a truck for shipment.

FIG. 29C illustrates an embodiment in which the container 2606 is provided with exhaust louvers 2902 and/or inlet louvers 2904. In this embodiment the fresh air inlet stream and the exhaust gas outlet stream may be provided, modulated and/or directed. For example, the inflow of fresh air can be lowered by partially closing inlet louvers 2904. In another example, the direction of the exhaust gas (e.g. down towards the ground, up towards the sky or any direction in between) may be adjusted by rotating the louvers accordingly.

FIG. 30 illustrates stackable power modules, e.g. fuel cell modules 100 according to embodiments. In these embodiments, the power modules include support structures, e.g. cross bracing or support walls 2700 located at the ends of the rows 2601 of power modules located on or in pallet or rack type containers 2606. In an embodiment, such as the embodiment illustrated in FIG. 30, a pallet may be slid into a set of shelves 2910, where the shelves form the stacking structure and are formed of either concrete or steel, thereby creating the hot and cold plenums for exhaust and inlet.

FIG. 31 illustrates a prior art shipping container from www.acecontainerparts.com which can be used as a container 2606 in one embodiment. The shipping container includes a flooring 4.2.16, side walls 4.2.2, a rear door assembly 4.3 and a roof panel 4.2.10. The shipping container also includes a ventilator 4.2.9 and a marking panel 4.2.5 on one of the sidewalls 4.2.2. The flooring 4.2.16, side walls 4.2.2, rear door assembly 4.3 and roof panel 4.2.10 are held in place with a front end frame 4.1.8, a rear end frame 4.1.5, a top side rail 4.1.9 and a bottom side rail 4.1.10. The flooring 4.2.16 is supported by cross members 4.1.11. The shipping container also includes a threshold plate 4.2.18 and a joint strip 4.2.17 running longitudinally down the center of the flooring 4.2.16. Forklift pockets 4.2.13 are provide to aid in lifting of the container.

FIG. 32 is a perspective view of a stackable power system 3200 comprising stackable power modules, such as fuel cell modules 100 or the co-generation (“Co-Gen”) modules discussed above according to an embodiment. In addition to the fuel cell modules 100, the stackable power system 3200 may include one or more input/output modules 14, fuel processing modules 16 and/or power conditioning modules 18. In an embodiment, the doors 30 of the input/output modules 14, fuel processing modules 16 and/or power conditioning modules 18 may lack the air inlets 42 and/or filters 40 of the fuel cell modules 100 that are shown in FIG. 8. Furthermore, fuel cell modules 100 that do not have an operating hot box 13 located inside and may have the air inlets 42 blocked with a solid blocking material. In an embodiment, the stackable power system 3200 includes a rack type container 2606 having two or more bases 20. The plurality of bases 20 may be spaced apart from each other and supported by support pillars 3202. In an embodiment, the bases 20 include cavities configured to receive the support pillars 3202. In an alternative embodiment, the bases 20 include protrusions on the bottom and the support pillars 3202 include cavities configured to receive the protrusions. In an embodiment, a back support 3204 is provided to add additional stability to the modules of the stackable power system 3200. The modules 14/16/18/100 of the power system (e.g. of each fuel cell system 10) are located on each respective vertically separated base 20 of the rack type container 2606. As illustrated, the stackable power system 3200 is a single vertical stack of two rows of modules. However, any number of modules or containers 2606 of modules may be stacked as desired, such as 3, 4, 5 or more rows of modules. In an embodiment, the stackable power system 3200 is formed by stacking containers 2606 of modules in which the containers 2606 have removable side panels which are removed after shipping. In one embodiment, shock dampers 2800 may be located between the modules and the respective underlying base 20.

FIG. 33 is a perspective view of a stackable power system 3300 according to another embodiment. In this embodiment, the stackable power system 3300 include a plurality of vertical stacks 2607 of power modules, such as fuel cell systems 10 located on rack-type containers 2606 having respective bases 20 and support pillars 3202. In this embodiment, each base 20 is configured to support two rows 2601 of stackable power modules. Preferably, the power modules are configured such that an air inlet plenum 2604 is formed between adjacent power modules located on the same base 20. In an embodiment, multiple rows of containers 2606 are provided. Preferably, space is provided between the containers 2606, thereby forming a shared exhaust plenum 2602 between the rows. In an embodiment, support beams 3304 may be provided for added support. Support beams 3304 may be provided oriented in a direction perpendicular to the major surface of the bases 20 to support the stacked power modules. Support beams 3304 may also be provided oriented in a direction parallel to the surface of the bases 20 to support the stacked power modules.

FIG. 34 is a perspective view of a stackable power system 3400 according to another embodiment. In this embodiment, each base 20 is configured to support multiple rows of power modules, such as fuel cell systems 10. In an embodiment, each base 20 is sufficiently large enough to support a plurality of fuel cell systems 10A oriented in a first orientation and a plurality of fuel cell systems 10B oriented in a second orientation different from the first orientation. In an embodiment, the second orientation is orthogonal to the first direction. However, the fuel cell systems 10, 10A, 10B made be arranged in many different configurations as illustrated in FIGS. 27B-27D. In an embodiment, the fuel cell systems 10, 10A, 10B may be configured to form shared exhaust plenums 2602 and inlet plenums 2604. In an embodiment, walls/partitions 3404 are provided stretching from the top of the fuel cell systems 10 to the bottom of the base 20 above if the distance between adjacent bases 20 exceeds the height of the power modules. In this manner, exhaust gas can be confined to the shared exhaust plenums 2602, rather than flow over the power modules and mix with the input air. In an embodiment, the lowest most base 20 is located on top of an electrical room 3402. The electrical room 3402 may house electrical equipment, such as transformers and computers used to control the stackable power system 3200. The electrical room 3402 may also be used to store spare parts, extra fuel, tools and the like.

An embodiment includes equipment for keeping process exhaust and cabinet exhaust segregated in the exhaust plenum. Another embodiment includes equipment, such as a blower or exhaust fan, to prevent backflow in the exhaust plenum 2602 (e.g. hot aisle), such as during a maintenance event. In an embodiment, blocking walls or pieces 3404 are provided to prevent backflow which could also block off empty slots in the stacked arrangement 2602. This may be used to facilitate future growth of power generator units not deployed at time of construction. An embodiment includes mechanical elements to block all recirculation paths.

FIG. 35 illustrates another stackable power system 3500 according to an embodiment. This embodiment is similar to the embodiments illustrated in FIGS. 32 and 33 and discussed above. Specifically, this embodiment includes a plurality of power systems 3200 of FIG. 32 comprising stackable power modules, such as fuel cell modules 100. The plurality of power systems 3200 may be configured in rows such that shared exhaust plenums 2602 and inlet plenums 2604 are formed, similar to the embodiment illustrated in FIG. 33 and discussed above.

In prior embodiments, the exhaust plenum 2602 and the inlet plenum 2604 are mechanically separated by walls or other partitions to prevent the hot exhaust from the exhaust plenum 2602 from entering the inlet plenum 2604. In an alternative embodiment, all or some exhaust from the exhaust plenum 2602 is recirculated to the inlet air in the inlet plenum 2604 to create direct pre-heating (by mixing) or through heat transfer. In an embodiment, blowers 3502 can also be provided to increase air inlet pressure and flow or to pull suction on the exhaust to increase exhaust flow as shown in FIG. 35. In an embodiment, the blowers can also add external air to the exhaust plenum to dilute exhaust flows and reduce the temperature of the hot exhaust flow to temperature suitable for service personnel who may be present in the inlet plenum 2604 while the system operates if the hot exhaust flow temperature is considered too high for service personnel presence. Alternatively, only a part of the hot exhaust flow may be recirculated into the inlet plenum 2604 through one or more limited size openings in a wall or partition between the exhaust plenum 2602 and the inlet plenum 2604 to maintain the temperature in the inlet plenum above room temperature but below a temperature which would be considered unsafe for service personnel present in the inlet plenum. In another embodiment, the inlet plenum 2604 may be sealed and pressurized to a pressure higher than the pressure in the exhaust conduit 2602 in a service mode when service personnel gain entrance to the inlet plenum 2604 or to a room in which the entire system is located. In other words, when a door to the room and/or to the inlet plenum 2604 is opened, a fan or blower is turned on to over pressurize the inlet plenum 2604 with room temperature air.

In an embodiment, when there is available space on or in a container 2606, the modules 100 are spaced out and gaps blocked as needed to prevent recirculation. In an embodiment, an exhaust duct from a bottom module 100 or set of modules 100 up to the next layer of modules 100 in a stack is provided. In an embodiment, a means, such as louvers, is provided within the exhaust plenum of a module 100 within a stack to close its exhaust off by section of a module 100 or for a complete module 100 without impeding exhaust of other modules 100 in stack. This is similar to a filter blocking device which prevents leakage from modules 100 to module 100 in a stack versus power module 2606 to power module 2606 leakage within a housing.

FIG. 36 illustrates another stackable power system 3600 according to an embodiment. This embodiment is similar to the embodiments illustrated in prior figures and discussed above. In this embodiment, the modules 100 are located inside a building 3602 containing a roof 3604. The modules may be stacked on bases 20, which may be floors of the building 3602 or mechanical supports described above. In this embodiment, the system includes an exhaust flue 3701 that terminates in a chimney 3606 which extends through the roof 3604 of the building 3602. The outlet (i.e., top opening) 3607 of the chimney 3606 is located above the top of the building air intake equipment 3608, such as an air handler, an air intake ducts, etc. located on the roof 3604. In this embodiment, the fuel cell system exhaust stream 3610 passes through the exhaust flue 3701 and the chimney 3606 before being provided through the outlet 3607 above the top of the building air intake equipment 3608. This prevents the exhaust stream 3610 from entering the building air intake equipment 3608, and complies with municipal building codes. In this embodiment, the plurality of vertically stacked power modules 100 are located in the building 3602 having the building air intake equipment 3608 located on the roof 3604 of the building. The exhaust flue 3701 is fluidly connected to the chimney 3606 located on the roof 3604 of the building 3602, such that the exhaust stream 3610 may pass either directly from the exhaust flue 3701 to the chimney 3606 or indirectly from the exhaust flue 3701 through an intermediate duct or pipe to the chimney 3606. The outlet 3607 of the chimney 3606 is located above the air intake equipment 3608.

Exhaust Heat Recovery Components

FIG. 37A is a perspective view of a vertically stacked fuel cell system 3700 configured for exhaust heat recovery and/or utilization, according to various embodiments of the present disclosure. FIG. 37B is a schematic view of the system 3700 of FIG. 37A and FIG. 37C is a schematic view showing optional elements that may be included in the system 3700 of FIG. 37A.

Referring to FIGS. 37A and 37B, the system 3700 includes cabinets 22 for the above described power modules 100, fuel processing modules 16 and input/output or a power conditioning modules 18 that are disposed in rows on one or more floors F of a building. The system 3700 includes an exhaust flue 3701 that includes one or more inner ducts 3702 and at least one outer duct 3704. The inner ducts 3702 may be configured to receive relatively hot reaction exhaust R from the hot box 13 of at least one of the power modules 100. The hot reaction exhaust R may comprise an exhaust from an anode tail gas oxidizer (ATO) located in the hot box 13. The ATO reacts at least part of the anode exhaust (i.e., fuel exhaust) stream from fuel cells located in the hot box (e.g., from a fuel cell stack) with air, such as the cathode exhaust (i.e., air exhaust) stream from the fuel cells to output oxidized fuel exhaust as the hot reaction exhaust R. The fuel cells (e.g., fuel cell stacks, columns and/or segments) are located in the hot boxes 13. The hot boxes 13 are located inside cabinets 22 of the power modules 100. The inner duct 3702 is fluidly connected to the exhaust conduits 3706 of the hot boxes 13, while the outer duct is fluidly connected to the exhaust conduits 301 of the cabinets 22.

In one embodiment, the system 3700 may include transfer conduits 3706 configured to fluidly connect the hot boxes 13 to the inner ducts 3702. The outer duct 3704 may be configured to receive relatively cool cabinet exhaust C from the cabinet 22 of at least one of the power modules 100. For example, the outer duct 3704 may be fluidly connected to the ventilation modules 300 attached to the cabinets 22 by a ventilation duct 301. In some embodiments, the flue 3701 may include a single outer duct 3704 that is configured to receive cabinet exhaust from all of the cabinets 22 and multiple inner ducts 3702 disposed in the single outer duct 3704. In other embodiments, the flue 3701 may include multiple outer ducts 3704 in which at least one inner duct 3702 is disposed. For example, four or more inner ducts 3702 may be disposed in each outer duct 3704.

In various embodiments, the system 3700 may include a heat exchanger 3710 disposed in at least one of the inner ducts 3702. The heat exchanger 3710 may be configured to transfer heat from the reaction exhaust R to a fluid. For example, the heat exchanger 3710 may be a boiler configured to heat water (e.g., water that is provided to the fuel inlet stream in the hot box 13) using heat captured from the reaction exhaust R. In other embodiments, the heat exchanger 3710 may be configured to heat the fuel inlet stream, such as liquid natural gas to generate gaseous natural gas which is provided to the hot boxes 13 as fuel for the fuel cells. In still other embodiments, heat captured by the heat exchanger 3710 could be stored using an integrated thermal storage sub-system.

The system 3700 may also include a diverter 3720. The diverter 3720 may be configured to direct a portion of the reaction exhaust R from the inner duct 3702 into the outer duct 3704. Accordingly, the diverter 3720 may be configured to prevent overheating of the fluid in the heat exchanger 3710.

Referring to FIG. 37C, the system 3700 may optionally include a reaction conduit 3712 disposed in at least one of the inner ducts 3702 and configured to receive a fuel from a fuel source and/or to receive unreacted fuel (e.g., remaining unreacted fuel, such as hydrogen, methane, etc.) from the fuel cells in the hotbox 13. A first catalyst 3714 and/or a second catalyst 3716 may be disposed in the reformation conduit 3712. In some embodiments, a mass flow control valve 3722 and a heat exchanger 3724 may be disposed on the reaction conduit 3712. The mass flow control valve 3722 may be disposed outside of the flue 3701, and the heat exchanger 3724 may be disposed inside of the outer duct 3704. In other embodiments, a carbon dioxide separator may also be disposed on the reaction conduit 3712, outside of the flue 3701.

The catalysts 3714, 3716 may comprise various fuel processing materials such as catalyst and/or adsorbents. For example, catalysts 3714, 3716 may comprise a reformation catalyst configured to catalyze a steam reformation and/or methanation reaction for higher hydrocarbons and sulfur species reduction catalysts such as zinc oxide, configured as catalyst particle beds and/or catalyst coated walls, fins or other structural features in the conduit 3712.

For example, in embodiments where a reforming reaction for a hydrocarbon fuel, such as C₃H₈ is performed by the system 3700, a fuel mixture stream of fuel inlet stream (e.g., C₃H₈) plus recirculated anode exhaust stream from the fuel cells is passed through the reaction conduit 3712 to be heated to a temperature ranging from about 250° C. to about 400° C., such as from about 300° C. to about 360° C. either in the heat exchanger 3710 and/or in the inner duct 3702, by the hot reaction stream R. In particular, the fuel mixture may be passed through a first zinc oxide desulfurizer catalyst 3714 disposed in the first catalyst bed in the conduit 3712 and then through a second C₃H₈ reforming catalyst 3716 disposed in the second catalyst bed in the conduit 3712. Then, the fuel mixture may be passed through the heat exchanger 3724 located in the outer duct 3704 or through the heat exchanger 3710 and the temperature of the fuel mixture may be reduced to a temperature ranging from about 125° C. to about 200° C., such as about 150° C. The fuel mixture may then be provided to an anode recirculation blower 3726 and into the fuel cells located in the hot box 13. In some embodiments, the fuel mixture may also be passed through a carbon dioxide separator 3728 disposed in the reaction conduit 3712, outside of the flue 3701.

In some embodiments, the reaction conduit 3712 may include fractionation equipment configured to use heat from the reaction exhaust R to perform a fractionation step on heavy hydrocarbon fuel or other chemicals where fractionation has value. In other embodiments, the reaction conduit 3712 may be configured to pasteurize and/or sterilize wastewater which may or may not be subsequently mixed with the fuel inlet stream to be provided to the fuel cells. In other embodiments, the reaction conduit 3712 may be configured to process solid waste products or comprise adsorption chiller equipment which uses heat from the reaction exhaust R to perform its respective function.

In some embodiments, the system 3700 may optionally include at least one thermoelectric generator (TEG) module 3718 disposed at an interface between the inner and outer conduits 3702, 3704. The TEG module 3718 includes a thermoelectric device which is configured to generate electricity using a temperature gradient formed between the inner and outer ducts 3702, 3704. In other words, a hot surface of the TEG module 3718 may be exposed to the relatively hot reaction exhaust R in the inner duct 3702 and a cold surface of the TEG module 3718 may be exposed to the relatively cool cabinet exhaust in the outer duct 3704.

In other embodiments, the inner duct 3702 could be used to create a source of heat to improve the startup timing and process for hot boxes which are not in operation by creating a small reverse flow of hot gases (i.e., of the relatively hot reaction exhaust R) from the hot boxes 13 operating at steady state to hot boxes operating in a startup mode. In still other embodiments, reaction exhaust R from the inner duct 3702 could be directed toward a down-stream heat engine process to generate additional electricity. In further embodiments, inner and/or outer duct flows could be directed toward heat pumps to enable multiplication of heat to increase heat output.

In various embodiments, the system 3700 may allow for an anode exhaust cooler heat exchanger to be omitted from the power modules 100 and the inner ducts 3702 may be configured to receive reaction exhaust directly from anode recuperator heat exchangers (which exchange heat between fuel inlet stream and anode exhaust stream of the fuel cells) of the power modules 100. Specifically, instead of heating the air inlet stream using the anode exhaust stream in the anode exhaust cooler heat exchanger, the air inlet stream to the hot boxes 13 may be heated in the heat exchanger 3710 located in the flue 3701.

FIGS. 38A and 38B are schematic views showing the operation of the damper 3720, according to various embodiments of the present disclosure. Referring to FIGS. 38A and 38B, when the damper 3720 is closed, the reaction exhaust R and the cabinet exhaust C respectively remain in the inner duct 3702 and the outer duct 3704. When the damper 3720 is opened, all or a portion of the reaction exhaust R may be diverted into the outer duct 3704. Accordingly, the damper may control the temperature of the heat exchanger 3710, by controlling an amount of the reaction exhaust R is supplied thereto. In addition, the damper 3720 may operate to bypass the heat exchanger 3710 to reduce and/or prevent exhaust backflow into power modules 100 that are being serviced.

In an alternative embodiment, the relatively cool cabinet exhaust C may be vented to atmosphere rather than being provided to the flue 3701. In this embodiment, the flue 3701 may consist of only the inner duct 3702 and the outer duct 3704 is omitted. The relatively hot reaction exhaust R flows through the flue 3701 while the relatively cool cabinet exhaust C is vented to atmosphere without passing through the flue 3701. Furthermore, while vertically stacked modules 100 are illustrated in FIGS. 37A to 37C, in an alternative embodiment, the modules 100 may not be vertically stacked and instead may be located only in horizontal rows.

FIGS. 39A and 39B are perspective views showing an actuator, such as for example a linear actuator 3730 that may be included in the system 3700, according to various embodiments of the present disclosure. Referring to FIGS. 39A and 39B, the linear actuator 3730 may be disposed within the ducts 301 and 3704 and may be configured to contract and extend to close and open the damper 3720, which may be a flap which in its open position extends into the inner duct 3702 and opens a passage between the inner and outer ducts. In an alternative embodiment, another suitable actuator, such as a rotary actuator or a pneumatic actuator may be used instead of the linear actuator 3730.

In other embodiments, the flue 3701 may be arranged horizontally and connected to horizontally arranged power modules. In other embodiments, the power modules 100 are not stacked vertically and are positioned in one or more horizontal rows. In one embodiment, fans are omitted for simplicity by maintaining the air pressure in the outer duct 3704 using the main air blower which provides air to the fuel cells in the hot box.

In summary, in one embodiment, a method of operating a fuel cell system 3700 includes operating fuel cells located in hot boxes 13 which are located inside cabinets 22 to generate electricity, providing a relatively cool cabinet exhaust C from the cabinets 22 to the outer duct 3704 of the flue 3701, and providing a relatively hot reaction exhaust R from the hot boxes 13 to an inner duct 3702 of the flue 3701.

In one embodiment, the method further comprises extracting heat from the reaction exhaust R in a heat exchanger 3710 located in the inner duct 3702. In one embodiment, the method further comprises opening a damper 3720 to divert at least a portion of the reaction exhaust R from the inner duct into the outer duct. In one embodiment, the method further comprises at least one of reforming, desulfurizing, methanating or fractionating a hydrocarbon fuel in a reaction conduit 3712 located in the inner duct 3702 using heat from the reaction exhaust R flowing through the inner duct.

Electrical Architecture

FIG. 40A is a schematic illustrating power flow through electrical architecture of a fuel cell system 4000 during system startup, and FIG. 40B is a schematic illustrating power flow through the fuel cell system electrical architecture during steady-state operation, according to various embodiments of the present disclosure. As would be apparent to one of ordinary skill in the art, the component “connections” described below are intended to refer to “electrical connections” unless otherwise specified. Referring to FIGS. 40A and 40B, the system 4000 may include a grid-parallel inverter module 4001 connected to at least one power module 100 by a startup bus and a fuel cell (e.g., steady state) bus, as described below. For example, the system 4000 may include multiple inverter modules 4001 that are each connected to multiple power modules 100. In one embodiment, each inverter module 4001 may be located in a separate housing 4022 from the respective housings 22 of the power modules 100.

The inverter module 4001 may include a steady-state transformer 4002 and a startup transformer 4004 that are connected to an electrical utility (e.g., power grid). The steady-state transformer 4002 may be connected to an AC/DC converter 4012. The AC/DC converter 4012 may be connected to a steady-state diode 4010 that is connected to a balance-of-plant (BOP) load. The startup transformer 4004 may be connected to a rectifier 4006. The rectifier 4006 may be connected via the startup bus 4007 to a startup diode 4008 connected to the BOP load.

The power module 100 may include a DC/DC converter 4018, a startup diode 4014, and a steady-state diode 4016. The DC/DC converter 4018 may be electrically connected to the AC/DC converter 4012 and fuel cells in the hot box located in the cabinet 22 of the power module 100. The DC/DC converter 4018 may also be connected to the steady-state diode 4016. The diodes 4014, 4016 may be connected to a BOP load. The startup diode 4014 may also be electrically connected to the rectifier 4006.

Referring to FIG. 40A, during startup of the system 4000, the fuel cells are heated until the fuel cells reach an operating temperature. Before reaching the operating temperature, the fuel cells may not generate an amount of power sufficient for the BOP loads. As such, during startup, the power from the utility is provided to the BOP loads via the startup bus. In particular, power flows via the startup bus 4007 through the startup transformer 4004, the rectifier 4006, the startup diodes 4008, 4014, and then to the BOP loads. The inverter 4012, converter 4018 and steady0state bus 4020 are not used during system startup.

Referring to FIG. 40B, once the fuel cells reach the desired steady-state operating temperature (e.g., 750° C. and above), steady-state operation of the system 4000 begins and power is provided from the fuel cells to the BOP loads. In particular, power flows from the fuel cells via the steady-state bus 4020 through the DC/DC converter 4018, the AC/DC inverter 4012, and through the steady-state transformer 4002 to the utility and/or to any local load. Power is also diverted to BOP loads as needed through the steady-state diodes 4010, 4016. As such, the rectifier 4006 and startup transformer 4004 are not used. Steady-state operation continues at all times when the fuel cells are hot enough to generate power, including when the transformers 4002, 4004 are disconnected from the utility (e.g., power grid), which accounts for almost all of the fuel cell's operational life.

In one embodiment, one or more inverter modules 4001 may be located on the lower level (e.g., lower floor F) shown in FIG. 37A, while the power modules 100 may be located on the lower level and on the upper level(s) (e.g., all floors F) shown in FIG. 37A.

According to the embodiment of FIGS. 40A and 40B, a fuel cell system includes power modules comprising fuel cells, and an inverter module electrically connecting the power modules to a power grid. The inverter module is configured to provide power from the grid to the power modules using a first bus, during startup of the system, and provide power from the power modules to the grid using a second bus, during steady-state operation of the system.

The construction and arrangements as shown in the various examples are illustrative only. Although only a few examples have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative examples. Other substitutions, modifications, changes, and omissions may also be made in the design, operating conditions and arrangement of the various examples without departing from the scope of the present disclosure. Any one or more features of any example may be used in any combination with any one or more other features of one or more other examples. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents. 

What is claimed is:
 1. A fuel cell system comprising: power modules that each comprise a cabinet and fuel cells disposed in the cabinet; and an exhaust flue comprising: an outer duct configured to receive relatively cool cabinet exhaust output from the cabinets; and an inner duct disposed inside of the outer duct and configured to receive relatively hot reaction exhaust output from the fuel cells of the power modules.
 2. The system of claim 1, further comprising a heat exchanger located in the exhaust flue and configured to extract heat from the reaction exhaust.
 3. The system of claim 2, wherein the heat exchanger comprises a boiler.
 4. The system of claim 2, further comprising: a damper configured to divert at least a portion of the reaction exhaust from the inner duct into the outer duct; and an actuator configured to open and close the damper.
 5. The system of claim 1, further comprising: a reaction conduit extending through the outer duct and the inner duct and configured to provide fuel from a fuel source to at least one of the power modules; a first catalyst disposed in the reaction conduit; and a second catalyst disposed in the reaction conduit downstream from the first catalyst, with respect to a flow direction of a fuel through the reaction conduit.
 6. The system of claim 5, wherein: the first catalyst comprises a metal oxide catalyst configured to remove sulfur species from the fuel; and the second catalyst comprises a reformation or methanation catalyst.
 7. The system of claim 5, further comprising: a carbon dioxide separator disposed on the reaction conduit, outside of the flue, and downstream of the second catalyst; and a heat exchanger disposed on the reaction conduit, in the outer duct, and downstream of the second catalyst.
 8. The system of claim 7, further comprising: a flow control valve disposed on the reaction conduit, outside of the flue, and upstream of the first catalyst; and an anode recirculation blower disposed on the reaction conduit, outside of the exhaust flue, and downstream of the heat exchanger.
 9. The system of claim 1, further comprising a thermoelectric generator module disposed between the inner duct and the outer duct.
 10. The system of claim 1, wherein the exhaust flue comprises a plurality of the inner ducts disposed in the outer duct.
 11. The system of claim 1, wherein the power modules are disposed in vertically stacked rows, and wherein the exhaust flue is located between back sides of two rows of the power modules.
 12. The system of claim 1, wherein: the fuel cells are located in hot boxes; and the hot boxes are located inside cabinets of the power modules.
 13. The system of claim 12, wherein the inner duct is fluidly connected to exhaust conduits of the hot boxes.
 14. The system of claim 13, wherein the outer duct is fluidly connected to exhaust conduits of the cabinets.
 15. A method of operating a fuel cell system, comprising: operating fuel cells located in hot boxes which are located inside cabinets to generate electricity; providing a relatively cool cabinet exhaust from the cabinets to an outer duct of a flue; and providing a relatively hot reaction exhaust from the hot boxes to an inner duct of the flue that is disposed inside of the outer duct.
 16. The method of claim 15, further comprising extracting heat from the reaction exhaust in a heat exchanger located in the inner duct.
 17. The method of claim 15, further comprising opening a damper to divert at least a portion of the reaction exhaust from the inner duct into the outer duct.
 18. The method of claim 15, further comprising at least one of reforming, desulfurizing, methanating or fractionating a hydrocarbon fuel in a reaction conduit located in the inner duct using heat from the reaction exhaust flowing through the inner duct.
 19. The method of claim 15, wherein the relatively cool cabinet exhaust from the cabinets flows in the outer duct of a flue in a same direction as the relatively hot reaction exhaust from the hot boxes flows in the inner duct of the flue. 